yeah I'd go for the qidi.
Flaxible pla is a flexible material made from pla.
I have no idea how it's amde but it is hands down the toughest material I've ever printed with.

Tpu = thermoplastic polyurethane - basically synthetic rubber.
It's usually a bit too floppy to be uch use and the elasticity makes it trickt to print with.

Unfortunately most retailers now seem to call ALL flexible filaments 'TPU'. So it's getting kind of hard to tell which are pla and which aren't :-(

flexible pla is similiar, but tougher, less elastic and usually a bit stiffer.
This means you can make fairly rigig things from it that are virtually indestructible. Short of using power tools - you just can't damage it.

It means you can make things with lifetime hinges :-)

We can probably get away with tpu. It's just finding one that's a bit stiffer than the others.
I suppose I'll have to try and figure out how thie bizarre shore hardness acale works.