>please do research into how crappy modern, mass-produced RVs are built.

Any brands you/Liz Amazing suggest?

Depends what you want...

First off, a travel trailer make a lot of sense because you decouple the propulsion from the living quarters. But, then you might need a big truck (depends on size of trailer - most mid-size SUVs and compact trucks can only tow ~5000lbs). Another plus is you can drop the trailer at camp and drive to town/trail heads/etc. Downsides are total length, two registrations and insurance plans, etc.

If you don't need to live in it long-term, one of the fiberglass shell travel trailers (Oliver, Escape, maybe Scamp and Casita, though they're lower spec). The less plumbing, the better. The simpler the better. Less to go wrong/leak. They generally max out around 20 feet or so - plenty for a week here and there, but less than ideal for full-time living.

If I wanted full-time, I'd probably skip the Class B ("ship in a bottle van-based RV") and Class C (van/truck chassis and cab with box bolted on the back) RVs and jump straight to a Class A (bus or commercial truck chassis with custom cab). Something like a slightly used Prevost (though that's probably still $500k+, so won't help if you're priced out of traditional housing).

not the parent but Airstream or any other RV with an aluminum or molded fibreglass body.

most RVs have thin skins glued to a type of particle board and right angle joins everywhere. those joins will leak and when they do, the leak is often imperceptible. the interior walls and subfloor will rot before you notice anything's wrong.

RVs with a molded fibreglass or aluminum body use overlapping panels to naturally shed water and the materials used don't corrode (caveats apply, eg galvanic corrosion of aluminum). generally this means the RV won't rot out unless the panels themselves are holed, which is unlikely. it's not uncommon to see an Airstream that's been sitting in a PNW field for 30 years and find that the interior is musty and likely mouse chewed but structurally fine.

of course the mechanicals -- frame, axles, gas lines, appliances -- all need to be maintained and they are more expensive compared to their non-RV counterparts, but if you're handy and aware of your limits, these don't have to be show stoppers.