If you buy an Aegis mod (not a pod mod, but the Legend, Max, or X) you can put any 510 atomizer on it, so that gives you adaptability going into the future. The same is also true, though, of any dual-18650 or single 2x700 mod with a 510 connector on it. Just so happens that the Aegis line is really good. My personal favorite is the Aegis X (uses a single 20700 or 21700).
As you see, every one of us will give different recommendations; we are far from cookie-cutter, but everyone who has responded to you so far is experienced and wouldn't steer you wrong.
I also agree with having an RDA for testing DIY. It's just so easy to yank out a little dab of cotton and put a fresh one in for testing a new juice - no $5.00 coil to mess up every time. Costs a penny or two instead of $5.00. Simple coils are just that - simple, require few tools and don't take much time to wrap, you just have to educate yourself a bit about how to be safe and accurate with your builds.
At this point in time, I would not suggest to anyone that they make a big investment in sub-ohm tanks, because it's so much harder to order vape supplies these days. If you're self-sufficient in the e-liquid arena, sooner or later you'll want to be self-sufficient in the coils arena too. Might as well be now. lol Do note that people seem to have a bit more trouble building and wicking RTAs than they do RDAs, and really, in comparison, it's super-simple to build an RDA. You probably should start there. A Dead Rabbit SQ (22mm) is a good starter RDA, and I think you can actually still find them. I want to say that Wetvapes.com has them.
Also agree that in your initial post in this thread, you are describing a quantum leap, and I personally agree that it's too much at one time. I would try coil resistance at between 0.4 ohms and 0.7 ohms to start with, 30 to 45W, and either 9 or 12mg nicotine. Vaping 80 to 100W through a 510 drip tip? You're describing the fires of hell right there, bud. Your atomizer and drip tip would need to allow a lot more air circulation than you'll get through a 510 drip tip.
It probably won't be long before you'll be able to reduce nic to about 6mg, and from there it's just up to you to find the balance of whatever level keeps you from wanting to smoke (assuming you used to smoke). I got to 6mg and stayed there, but I have ADD, and nicotine is my ADD med. I don't intend to reduce any more until I get a lot nearer to the end of my stash.
Don't be shy with questions. As you see, we aren't reluctant at all to answer questions. It's exciting to see a new person just starting out - which is what I was when I came here about three years ago, and almost everything I know, I owe to the helpful, generous folks at VU. I came here using single-battery box mods, Kabuki clone tanks, and Nautilus coils. They've taught me (and a lot of other people) a lot.