WalkingPad R1 Pro. I thought the ability to run would be a plus, but honestly, I've only used it for running twice (I'd rather run outdoors than stare at a wall, tv or computer).

KingSmith walking pads can be folded and take less space. R1 can also be stored vertically, but I always keep it horizontally for convenience.

If I had to buy one treadmill again, I would chose either a regular model or a cheaper foldable model. I would probably lean towards a smaller and cheaper regular model since I believe 40cm x 80cm (16in x 32in) is enough to walk and is not that big.