@BlueTrin
1. From a purely financial point of view, the price differential of having your own gear (even without ongoing maintenance) verses rental can be very hard to justify. That said there is a great deal of satisfaction from having and using your own.
2. Given yoru location - even with your aversion to cold water diving, I would still recommend investigating BSAC clubs. You don't need to be a BSAC certified diver to join. Apart from having a decent social group of fellow divers, they often have regular pool nights where you can keep yoru skills up to date as well as checking your gear out before a trip. Nothing worse that having your gear not function on a trip after a period without use
3. Look carefully at gear markets as "travel gear" the differences in size and weight is often not that big compared with normal gear and not worth the extra cost. Chose what you feel is best for you
With Regs. My Reg stock (far too many) is exclusively Aqualung and Apex. Both are great robust. The Mikron is a great reg (although I use Legends) and the Apex XTX 50 is a great performer (no need to look at the 100 or 200)
4. For Airline travel our colonial cousins on the West of the pond have more liberal hand luggage allowances than Europe and ME. All my gear except computers goes in the hold. I use obvious dive bags, because they generally fit my needs, and while some people believe it's advertising you hav dive gear, my experience has been in many many trips that dive gear doesn't get stolen because its bulky, has no real resale value unless to other divers so is hard to get rid of.
My regs and BCD's are packed sensibly. that is either in a padded bag (for the regs) or wrapped and protected from sharp objects.
It's worth remembering when choosing a bag, that while it might seem great in the shop, how easy or practical is it on rough surfaces or beaches etc. If I'm going on a liveaboard I'll pack a net bad and use that to move my gear to a boat, leaving my big bulky bag in the shore store. My personal arrangement is that small electronics (dive comp, tablet, phone chargers etc) go in a back pack with whatever else I need for teh flights, dive gear in one bag and clothes etc in another to reduce bag size and weight. I'm a big fan of North Face as they seem to hold up well to travel abuse
Learn the basics, how to change hoses and O-rings on regs etc and take a very basic tool kit (adjustable spanner (wrench) set of imperial and metric allen keys (especially if using Din) so you can at least be a little self sufficient if you have an issue, but better to fully check and dive your gear before a trip (hence pool practice)
Good luck with your decisions and future dive trips