https://www.amazon.com/dp/B00Z9C4CT4/ref=cm_sw_r_sms_apa_i_njmVEbGT00B6C

These little guys from Sistema are my go-to. They're the best option I've discovered, and I have traveled internationally multiple times with these as well.

So, based on what you described so far, really the hardest part is about storage and refrigeration. But there are some items and tactics that might help.

The one consistent thing you have is your car, so setting up a dedicated area in your car for transporting your cooking and storage materials is crucial. I also think you need to break down your meal prep from one day a week to a few (I'll get into that in a moment) and rely on fresh, quick grocery runs when possible.

Here are a few of my favorite easy prep ideas:

1. Steam veggies in frozen bag - buy the smaller ones and eat the whole thing, or get fresh veggies and steam in a reusable steamer container: https://smile.amazon.com/Sistema-Microwave-Collection-Steamer-Large/dp/B005D6XZ4O/ref=pd_bxgy_2/133-3482367-5870229?_encoding=UTF8&pd_rd_i=B005D6XZ4O&pd_rd_r=065e1af9-015e-4991-a2a3-e924c19ac2c9&pd_rd_w=eJM4r&pd_rd_wg=EglHS&pf_rd_p=fd3ebcd0-c1a2-44cf-aba2-bbf4810b3732&pf_rd_r=5MNHXQ9RRZHMBRPK66DV&psc=1&refRID=5MNHXQ9RRZHMBRPK66DV
2. VeeTee pre-cooked rice - I've tried every pre-cooked rice available, and these are by far the best. I ship them to me via amazon, and one container is exactly two servings. https://smile.amazon.com/stores/Veetee+Rice/page/44245AA2-25E1-436D-97EC-E18273606922?ref_=ast_bln
3. Potatoes - Potatoes can be great, especially once you learn how to microwave one into a baked potato. I'll also argue here, Wendys has a really decent plain baked potato. https://smile.amazon.com/OBTANIM-Microwave-Potato-Reusable-Cooker/dp/B07QR2T2MX/ref=sr_1_5?dchild=1&keywords=baked+potato+microwave+cooker&qid=1621611223&sr=8-5
4. Pre-packaged foods - I know everyone will tell you to stay away from them - too many extra artificial ingredients, to much sodium, etc. But you are honestly not in a position to brew up your own chicken stock to then make a homemade chicken noodle soup. Look at the labels, Look at your macros, including sodium, and make choices that blend your need for healthy and your limitations on what you can and can't do. I always use canned soup (except for my chili, down below) and a lean cuisine is a decent choice for very low calorie food. I look for low sodium items if possible. Take a good look around your grocery store for individual sized portion control items. Think everything, from individual olive cups to pickle chips, to mac & cheese. Yes, you're spending more for the individual sizing, but they are made for people like you.
5. Chicken - at least at first, try the pre-grilled chicken packets as they are resealable and can keep pretty cold (don't buy on amazon - they're at all the grocery stores, but I'm including the link so you see what they look like) https://smile.amazon.com/Perdue-Carved-Chicken-Breast-Grilled/dp/B06XC1WHYK/ref=sr_1_2_0o_fs?dchild=1&keywords=perdue+chicken+strips&qid=1621607683&sr=8-2
6. Sauces - for me chicken requires some sort of extra flavor, so I like to use a few low calorie dressings ore sauces to amp up a meal. Downside is that they require refrigeration. I always keep an italian dressing, low fat sour cream, a Thai peanut sauce and a Tzatziki in my fridge, and with a good size cooler, you can keep them relatively refrigerated. You may also consider putting them in smaller travel containers like these (I use Sistema, but there are plenty of good brands out there - I like that when I screw the lid on you can feel the click at the end to know its on tight) https://smile.amazon.com/Sistema-Collection-Bites-Storage-Containers/dp/B00Z9C4CT4/ref=sr_1_3?dchild=1&keywords=sauce+containers+sistema&qid=1621608980&sr=8-3 To protect these you might even put these containers in a large yeti or water jug for extra protection
7. I also recommend that you look at a restaurant supply store for individual portion control condiments, if you can't live without your mayo or frank's hot sauce: https://www.webstaurantstore.com/85/condiment-portion-control-packs.html
8. Make a point of leaving the office and routinely hitting up a grocery store - pick up just fresh or frozen fruit and vegetables for dinner, the next day's breakfast and/or lunch. Once it's routine for you, it won't feel like a heavy burden and you always get the freshest produce.
9. Chili - I make a chili with ten servings, and freeze most. This you can prep on the weekends, pack it up, freeze them, and use them to help keep the cooler chilled. I don't use expensive containers, but i do use locking screw top ones like this: https://smile.amazon.com/Ziploc-Twist-Container-Medium-Pack/dp/B010OVMETY?ref_=ast_sto_dp
10. If the hotels you stay at don't always include a fridge (or worse, fill it with stuff) If you have room in your backseat or trunk, I'd get a small dorm fridge like this: https://smile.amazon.com/dp/B01DZQI70K/ref=emc_b_5_i and a foldable trolley, and just wheel it in and wheel it out. https://smile.amazon.com/Aluminium-Folding-Lightweight-Foldable-Portable/dp/B01K1RUSU8/ref=sr_1_6?dchild=1&keywords=foldable+trolley&qid=1621610221&sr=8-6
11. Plate your food whenever you can - While I did not travel, I always kept two place settings at work in a box - two forks, two knives, two spoons, two soup bowls, two plates. Plating makes it feel like an actual meal and gives you an aesthetic balance that you might not realize you're missing.
12. I'd recommend this for anyone starting a food lifestyle change - what foods are you not willing to give up? Take those foods and build them into you routine. I LOVE cheeseburgers. LOVE hot sandwiches. So, rather than say no to them for the rest of my life, I build them into my calorie and macro counts. Don't say no to an item because it may seem "unhealthy" (well, say no to fried butter sticks, because there's no healthy to that at all, but otherwise there's usually wiggle-room)

This will seem like at first its taking over your life, and honestly, it will. You're literally packing up your car to feed yourself every week, and it will require daily and weekend prepwork to do it. But trust me, building this habit now will make you happier in the long run. Other than the refrigerator, everything I listed can be put into a solid size box and carried with you by car. I also recommend a solid wheeled cooler to keep in the car as well.

Wow those seem huge now lol. I love the sistema containers because they snap closed and stuff but honestly the bento one seem too big for anyone with wls. I loved bento boxes before but honestly I had to stop using them because of their size. Plus I like foods that are slightly brothy or moist like chili and they have a tendency of leaking into the other compartments sometimes so it could ruin whatever you had in there if it was for a different meal. If you think about it, the sistema one holds like 55 oz. I dk how far postop you are but at almost 5 months I can have about 4-6 oz or 2/3- 3/4 cups depending on the food and that’s like at max if I feel like finishing what I packed. It’s not uncommon for patients even years out to have a 1 cup max which is only 8 oz. A 55 oz bento is like 4 or 5 meals worth of food at least lol. I also find that when I over pack or use larger containers I have a tendency of wanting to eat more or finish it even if I’m approaching full which is a bad habit to fall into because you sort of eat against your restriction and can lessen its effect. The kids bento box seems a bit smaller and more reasonable with the multiple smaller spaces that would be ok if you’re pack multiple small portions for your whole day that you don’t mind going together. Honestly I started packing a few of the mini sistema containers like this or like the mini bites in my lunch bag instead. Because then I can have some variety without worrying I’m getting chili on all my food or something haha. Ziplock also has some twist and lock containers that are 4 oz and work great. If you still want to go for a bento then just be cautious of the size it holds and try to stick to things that are sized for children and as crazy as it sounds I usually buy Tupperware that have good reviews for quality but some very negative reviews from people are angry about how small it is and how little it holds and how they couldn’t use them because it wasn’t what they needed. Those are perfect for us postop lmao. I usually usually shop around for Tupperware that’s max 8 oz or less. Because that gives me room to meal prep but also not too much room to overfill it. Good luck finding something that works for you personally!

Edit: as far as food ideas, I usually always take 1 fairlife shake. Breakfast options are like 4 oz of plain nonfat Greek yogurt with maybe a strawberry or two inside or I do some protein oatmeal. For lunch I pack a Starkist packet of chicken or tuna, a little Buffalo sauce and an ounce or two avocado and 4 Flackers flax seed crackers so I can do like mash it up and do a Buffalo chicken/avocado salad on “crackers.” Sometimes I do a little Tupperware of chili, taco filling, or whatever meal I made the night before. Occasionally I’ll do just protein bar or humus with some protein chips. That’s all I pack for work honestly because I’d rather focus on drinking fluids throughout the day than eating a whole bunch. Then I eat again when I get home. I used to pack a ridiculous amount to take to work and then still buy more stuff while out but honestly postop I would rather just supplement with another meal or something in the comfort of my home if I don’t feel like I ate enough throughout the day.