Moto Razr 2020 foldable smartphone (a model earlier than the Razr Flip 40 you mentioned) can be had for $300 to $400 as a refurb/second hand. USA models for AT&T and T-mobile are very common.

I don’t find the battery life bad, but I may not be a heavy user by comparison. I love the small form factor, and unlike the Samsung Flip, the Razr doesn’t crease the screen (the hinge expands inside to keep it in a U spaced shape).

I don’t personally see the appeal of a foldable phone that folds out larger to a square aspect ratio, but ones that keep the normal smartphone aspect ratio (like Samsung flip and Moto Razr) and fold smaller are great!

Lastly, being able hang up the phone call by closing it is very satisfying.