I've considered things like Soylent in the past, though I've heard that they can cause gas and other gastrointestinal issues. I'm in an office most days of the week, so that's something I'd be a bit worried about.
If you're not used to having a healthy nutritional intake, or fiber intake, and then switch to Soylent for multiple meals all at once, then yes, your body can get GI issues. They sell single bottles at 7-11 & other places, so if you want to give it a try, try just drinking one for breakfast & seeing how you do. It's kind of like eating beans when you haven't eaten beans in awhile...your gut flora isn't used to them & can create gas, but once your body adjusts, it's fine.
I think most of the issues happen when people switch from eating a really poor diet of fast food & junk food to two or three meals of Soylent right off the bat...it's kind of a shock to their systems, haha. I call it "emergency food" because it's really handy when I need to run out the door in the morning or if I'm so busy that I have to work through lunch or if I'm stuck at work late & don't have time for dinner.
I keep a box in my desk drawer & a couple bottles in my bag just in case! That way I don't have to cave to the vending machine or fast-food or other low-quality food options...hunger goes away, body gets fed, it's pretty cheap for a meal with 100% nutrition, no dishes to do, no meal to prep. Pretty handy! I don't use it full time, but it is really nice in a pinch!
I do have access to boneless, skinless, chicken thighs and breasts.
Chicken is great because you can do so much with it. I use this procedure a lot:
https://asweetandsavorylife.com/recipe/how-to-cook-tender-juicy-not-dry-chicken-breasts/
Except I use a marble rolling pin & a Ziploc gallon bag to smash it (I like how the texture comes out with the weight & shape of the marble rolling pin better). From there, you can add salt & pepper and you have a great piece of chicken ready to go, or you can dress it up with some spices or sauces. For spices, you can go simple with something like seasoned salt, or a little more complex like lemon-pepper. McCormick sells little packets of spices in all kinds of different flavors, as well as larger bottles of pre-made mixes, so all you have to do is cook the chicken & sprinkle them on!
https://www.mccormick.com/grill-mates/flavors
Here are some sauce ideas:
This way, you're eating cheap & healthy, but you're also getting a pretty good variety of flavors. You can create a variety of textures as well:
It's easy to create some variety with different kinds of rice (brown rice, white rice, Rice a Roni, Spanish rice, etc. - you can buy them in individual packets or boxes) & different vegetables (frozen are easy, and the new packaging lets you steam them right in the bag in the microwave!). A 12-pack of dinner rolls or buns usually goes for a couple bucks in the bakery. So a few meal ideas might look like this:
The core idea in each meal is simply chicken breasts, but there's a million ways to dress up chicken to be awesome, so you can keep your food budget low, but still have a variety of flavors & textures, all while having each dish be easy to make. I'd recommend investing in either some Tupperware-style plastic or glass containers, or else some disposable meal-prep containers with dividers, because then you can bake a whole sheet of chicken nuggets or Mexican chicken, divide it up into half a dozen meal-prep containers, and stick it in the freezer so that you have stock & so that it doesn't go bad so quickly that you have to eat it all in one week & then get sick of it, haha!