Most of them are rated for several hundred pounds and I know some large people who’ve used them. The Aeron for one also comes in a large seat size. The key is the frame underneath that attaches to the pneumatic cylinder — how sturdy, the support structure, etc. Cheap office chairs are just a plate screwed into the bottom of the seat
You are right that the used market for them sucks now
I don’t know of a particular $200 chair to recommend, sorry. Used and plain Steelcase Criterions are the cheapest around me, $50 and a drive to the liquidator