Hi, welcome to ECF, the only dumb questions to ask are the ones that
aren't asked and later cause problems. I think one of my early questions had to do with nasal vaping (long story, and mouth surgery) so trust me, this board has seen its share of questions (and yes, I got useful answers on that one).
You have my quitting setup (now gifted to the husband) and I liked it a lot (but I am firmly in the MTL camp, not really the DL-- lower ohms, more wattage, more vapor per puff and draws less like a cigarette, and usually used with lower nicotine levels). You are correct that a backup device is really essential). If all your experience has been mouth to lung, you could choose your next device (or tank, or kit) based on the ability for it to do both. A dual battery mod of some sort (tons of options at various price points and varying options) with a more "sub0hm" tank like the Crown Uwell (ideally the original as it has the most options for various coil heads, up to I believe 1.2 ohms, but also much lower resistance option coils). It's a well liked tank, coils generally get good life, and they last a long time). If you wind up being more MTL, the worst thing that will happen with your bigger box mod is you will enjoy VAST battery life, etc. It would require buying an external charger and some batteries, and that is a whole topic in itself. But, you have many options moving forward, and it's really
rare for someone to land on their "perfect" setup on their first try, although it does happen. Since backups are necessary in any case though, you have nothing to lose by branching out either.
But you maybe want to hang out a while, ask more questions, check out some ECF approved vendors and their offerings and etc.
Welcome to ECF, I'm glad you joined and I wish you much more success this time!
Anna