I think it will be really important for you to go to a good shop and try them out. Maybe identify a couple of brands you want to look at and then check their websites for stockists local to you.
If the shop has a demo weighted "baby" to put inside then even better.
Handlebar rather than two handles will be imperative, but not all handlebars are equal. Some of them are clearly designed to be used with two hands, not one. I'd look as how the height adjusts. One that is telescopic should be fine. One where you "angle" the handle up and down is likely to struggle with being used one-handed.
Check the recline mechanism, the mechanism for taking the seat unit (and/or carrycot) on and off as well as the fold and push.
Try carrying it when folded.
Try pushing down on the handle to lift the front wheels as though to get up a kerb or step. If the shop has any steps, try the opposite.
Try changing direction sharply or maneuvring around tight spots.
Check whether it has built in hooks for attaching a changing bag. Hanging them off the handles, or adding third-party hooks where none were actually designed to be used, will put extra strain on your buggy. Or you could opt for a rucksack style.