Just my own .02 on stuff. Yes it can be overwhelming but it's much more varied than smoking. Not sure if you vape or not already or just getting into it. There's different style of vaping, mtl (mouth to lung) like smoking. Where you pull in the drag with your mouth then inhale the mouthful of vapor to the lungs. DL, dtl (direct lung, direct to lung) is a bit different from smoking. More like hitting a 'water pipe' in that you just inhale the vapor directly. I don't know about others, I experienced a bit of coughing until I got used to it switching from mouth to lung. Most subtanks (like the skrr) are direct lung designs and chances are if you try to mouth to lung them like a cig you'll choke. Just because it's a wide open hole for the vapor and no resistance really. Not like a cig with a filter. Some people like the throat hit, I'm one of those who has a sensitive throat after 20yrs of smoking and several years of chronic coughing. I'm not big on throat hit, I find the deeper lung hit/inhale of direct lung vaping with lower levels of nicotine to be more satisfying. Personal preference and you may not know what you prefer until you try it.
The luxe is a good mod and the nice part with external battery mods like that, they're versatile. You can put quality batteries in them, charge them externally so that means a device isn't down for hours recharging. So long as you have an external charger and a couple pair of batteries, let one set charge while vaping on the other set and swap back and forth. Having a 510 (nearly all regulated box mods do) means you can mix and match atomizers. You can throw a subohm tank on there and vape high wattage, warmer to hotter vape and big clouds, direct lung. You can pop a smaller tank on there and vape mouth to lung with lower wattage. Rta's (rebuildable tank), rda's (rebuildable dripper) will fit and connect/work. The zeus x would work with it just fine. Just keep in mind the zeus is a direct lung style atomizer, don't consider it if you're planning to mouth to lung vape like a cig. For mouth to lung, maybe something like the expromizer v3 or v4. The v3 is a bit larger, holds 2 or 4ml, the v4 is top airflow and holds 2ml of juice.
The expromizer v3 is on sale here for cheap, $8 + ship.
https://www.everzon.com/expromizer-v3-fire-mtl-rta-4ml.html?sscid=91k3_6s65b&
The zeus x you mentioned, $20 here at vapewild (reputable US vendor, fast shipping, free shipping orders $40+).
https://www.vapewild.com/geekvape-zeus-x-rta/
When it comes to rebuildables, either rta or rda, yes it's cheaper. Again lots of options. You can buy spools of plain wire of different metal types, kanthal a1 (wattage mode only), nichrome like ni80 or ni90 (wattage only), pure nickel ni200 (not to be confused with nichrome, temperature control only), titanium (temp control only) or stainless steel with 316L being one of the more common types of stainless (can be used in either wattage or temperature control). Using those plain spools you can unwind a few inches, wrap it around a jig either a dedicated vape coil jig, a smaller screwdriver, a nail or whatever to form it into a coil. Another option is a spool of more complex wire, clapton, fused clapton etc. Same deal, wind some off and wrap it around a jig to give it a coil shape. Spools of wire run around $4-7 and contain enough wire to make like 50+ basic roundwire coils.
You can buy packages of premade/preformed coils with fairly long legs/leads so you can install it and cut off the excess to fit whatever atomizer you use it with. Some companies like coilology have variety packs like their 7 in 1 kit. 7 different style of coils, 6 pieces of each so 6 coils or 3 pair for dual coil atomizers. 42 coils in all for like $12-15. You can buy premium handmade coils of fancier builds like fused claptons, aliens etc and price varies. Somewhere around $10-20 a pair usually which sounds expensive except good quality coils can be used for 3-4mo, maybe longer. Even cheaper mass produced premade coils you don't have to throw them out every time they get dirty. They can be cleaned, left in place and just new cotton put in place to replace the old. In that regard, coils used in rta's or rda's last a lot longer than those in subohm tanks like the prefab cartridge/coil head design. Main thing that goes on those, coils get dirty, cotton gets dirty and wore out but there's no easy way to replace the bad cotton and clean the metal coils.
When it comes to juice, really hard to say what you'd like. Flavor is very subjective even among retail ready made juice/flavors. Some people will love one company or flavor and hate another or vice versa. You really won't know until you try. DIY juice is much cheaper. The downside to that, it's like learning to cook all over again. Be prepared for some recipes to turn out better than others, not all are going to be winners. It's a little expensive to start but cheaper in the long run. When I started diy fairly recently, few months ago, I bought a starter kit from nicotine river, a dozen or so additional flavors, a couple extra bottles of vg (I generally vape 75vg/25pg or 80/20, thicker juice so I use vg at a higher rate). I also grabbed a digital scale for measuring by weight. Spent around $100-120 or so to start. The breakdown on juice costs, around $4/120ml of finished juice and I've made a good 1500ml of juice so far out of those supplies. I'm running a little low on vg (cheap), will need more nicotine sooner rather than later and have used some flavorings more than others. So while I've used up a couple flavoring bottles completely, out of 28-30 bottles of flavoring I bet I still have 70% of my total flavoring left. But it's like cooking, if you're making a cake you can have plenty of sugar and flour but if you're missing eggs you're sol for most cake recipes. Some things you use more than others and won't know until you get into mixing. Some things like flavorings you'll build up over time, things like scales once you purchase one you've got it so to keep making juice isn't as expensive as starting out.
Keep in mind the cost I gave was a worst case scenario. I bought small bottles of flavorings, smaller bottles of vg, pg, nicotine. Once you find a recipe you really like, maybe instead of buying 10-15ml of flavoring for $4-6 you get a 4oz bottle of it for xyz and cut your price per ml in half. Same with anything, buying in bulk is usually cheaper. You just don't want to start off that way, get a flavor you can't stand and realize you didn't save yourself anything. Not knocking diy juice, I do enjoy making my own as well as the cost savings. But it's not like a squirt of this and a squirt of that and in 5min I made an award winning flavor combo. Understanding the flavors and how they work with one another can be really involved if you're real picky. Not all juices have to have a ton of flavors, some are good with just 1 flavoring or 2-3 flavors mixed. Read/watch some at diyordie's Youtube channel (they have a website as well). Lots of good info here as well, there's a whole diy ejuice section where people share recipes or deals on supplies. I wouldn't discourage you from diy but if you're already new to vaping, maybe take it one step at a time so you don't overwhelm yourself is all. It can be a lot to absorb and get familiar with trying to start out making your own coils, making your own juice and rather than get frustrated and throw in the towel on it.
Some places to check out for more affordable juice, vapewild, omvapors, the sauce la, brokedick. Vaping is one of those fields or industries where there's tons of sales and discount codes online to various places. Major holidays like labor day, veterans day, thanksgiving, christmas, black friday etc as well as random sales so have a look around the web or check out vape groups on facebook or check the deals sections here under 'deals and steals'. There's a lot of sections here in the forums for just about anything you can think of. Folks selling off their used gear, discussing hardware, making diy ejuice, places discussing batteries and which ones to use. So if you have more specific questions, posting in those areas of the forums you'll likely get plenty of good advice. This forum's helped me a ton, like you I didn't know squat about vaping. Folks here have always steered me in the right direction and given me good options or a heads up on pitfalls to avoid.