I have to repeat myself, old used lenses with flex cables aren't worth the money those boomers demand.
Those flimsy plastic sheets with circuits printed on will grow brittle and break guaranteed, they'll lose focus/zoom/IS function and become worthless. Manual old glass might develop fungi, maybe the aperture controls freeze because of old grease. That can all be fixed easily because they're designed to be serviced.
Not so much with recent autofocus gear
Fixing it means complete disassembly which risks further damage and dirt ingress if you diy, professionals charge good money for that service for a reason. That's only viable for pro grade film lenses

RT: https://poa.st/objects/ab884a78-1b85-42a7-8e45-58b6bfba177e