I wouldn't recommend buying an expensive smartphone, such as the iPhone Pro, Pro Max, "Ultra", or Fold, without an AppleCare+ warranty. Whichever one you buy, those are too expensive not to back up with a warranty.
I use a case and screen protector. My last phone before I got my 13 Pro was a 7 Plus and that baby lasted me six years. Not a single repair needed.
I think I will be fine, because unlike most iPhone users I actually take care of my phone and don’t do stupid stuff with it.
To your second point I would add that by the time Apple makes an iPhone Fold, which Apple analyst Ming-Chi Kuo says won't come until 2025 at the earliest, you're not going to see an iPhone Fold suffering from bad design. The latest foldable phones have improved in durability since the first ones went on sale, and the technology is going to keep getting better before the iPhone Fold debuts.
But then comes the other issue with foldables: Why would I buy one? It’s a cool concept, but what use does it give me?
“We can have bigger displays!” But 6‘1 is plenty for me. I don’t need anything bigger. If I did I would’ve gotten a Pro Max.
“It protects the display from scratches in the pocket.” My screen protector already does that.
”It looks cool.” It does but the cost and reliability is too much, combined with that god damn crease. Plus I don’t care about phones like most do. I just want a phone that works which is why I have an iPhone instead of the more outlandish Androids.
So while an iPhone foldable will probably be good, I can’t see a reason for me to get one.