The problem is that I need to also get E-Juice, Devices and Coils every month to stay off cigarettes. But I'm also trying to get DIY supplies before the Ban-ocalypse hits.

At this point you have to prioritize your needs. First thing would be nic, second a new setup. TBH a pod kit wont last as long as a decent mod and rebuildables, not to mention coils are a money sink. Look for a decent 2 battery 18650 mod (Aegis legend for durability imo, mines going on a year and a half with no issues) and a MTL atty since you like the Caliburn. Those 2 would be around $60.

I've been advised to get

Nicotine for 3-5 years to store in the freezer

River supply or liquid barn are both decent places for nic. Personally I would go river supply as you can pick up nic, some empty bottles, vg/pg and a few flavors for $50 to hit free shipping.

and Devices first (at least two mods preferably MTL Tank and box). Because I need a few Rebuildables and MTL because I'm mainly vaping to stay off cigarettes and prefer MTL

See above- I dont vape MTL but IIRC the berserker and ammit should be decent but research these (both are drippers I believe, may have rta versions)

Question about my Premade Juice I need to mix with Premade Juice to lower strength:

I also have some juice Salts from TBD that where all 50mg which is way to strong for me. I want to get blunt tip syringes kit that has 10ml, 5ml, 3ml and 1ml syringes

Skip the headache and just get a scale from amazon. I have a cheap $15 one ( https://www.amazon.com/dp/B07LGWHNBG/ref=cm_sw_r_cp_apa_i_7-lsEbD9PG8JS ) that works for smaller batches.

"I have the following Liquids:*

• Mango at 2x 30ml at 25mg each.

You will need 4 to 8 bottles at 0 nic to dilute this to your desired potency. Or, add vg pg and a couple mango concentrates (do some reading on the 'good' ones) to your pre existing juice to stretch it.

• Lemon Squares: 1 30ml bottle of 0mg and a 30mlbottle of 50mg.

You need 2 or 3 30ml bottles of this in 0 nic to dilute.

• Blueberry muffin: 1x 30ml of 0mg and 1x 30ml of 50mg.

Again, 2 or 3 30ml 0 nic

• Mystery Flavor: 30ml - 50mg

3 or 4 0 nic 30mls

What are the best DIY kits?

No kits are worth it, need to research and build an order to your tastes.

What does everyone recommend?

So you have $180 to $240 to spend depending if you spent this months budget already. If I was stocking up I would spend the first $60 on nic alone (well, enough to hit free shipping, so a bunch of nic and a few 30ml bottles to mix the already owned juice into, concentrates if money allows.) Second 60 would be on a device and atty. 3rd 60 would be a backup mod and atty. That is March/April/May. From there all other purchases (vg/pg, concentrates, bottles, scale, wire, batteries and cotton) should be legal and not an issue to obtain.