Wife has owned a Z fold 2 and 4. I've owned a Surface Duo 2. My wife refuses to go back to a non-foldable. I preferred the dual independent screens of the Duo over the single large screen of the Z Fold. I hate using my single screen device now. When you get use to browsing the web while watching youtube, its hard to go back. I have my eye on the Oneplus Open, which seems to straddle the fence between the Duo and the Z Fold.
OP, there are two weak points on the Z fold. One is the crease in the middle of screen, and the other is the outer hinge. If dust gets in the gaps of the hinge or you bang it, your device will not open all the way. I have a Fold 2 that only opens 95% of the way. It was replaced with a Fold 4 that has now developed a black spot in the crease. They arent durable devices, but my wife doesnt care, she loves it and is going to ask for the newest model when the spot grows.