Which is why adcs don't go midlane and shouldn't ever have to deal with zed diving them 1v1? In the current meta a Zed is not very likely to win their lane as he can't really beat the rylai rush kite mages due to their strong waveclear.
Zed's not much better at diving top than most other midlaners and if he tries to dive bot when they're shoved up to their tower you need to have your jungler there and midlaner coming in. If your team doesn't do that and you get dived 4v2, lose the tower, lose like 12 cs, and dragon afterwards then your team is stupid and didn't deserve to win.
Literally any midlaner can do that if they have a reasonably tanky jungler who can pull tower aggro while they burst down botlane 4v2.
Being "forced" to buy hourglass isn't OP as any AD midlaner does that just like any AP toplaner "forces" you to buy SV or hex. It's just the most effective item against them and sometimes wins you the lane with 1 buy. Are you saying that having items that hard-counter you is OP?
And the adc isn't forced to buy a GA against zed as your support is probably running exhaust and your team has enough CC to just kill him if he ever yolo dives for you without trying to deal with your frontline first.
Every class has something they're good at and something they're bad at, ADCs are not good at towerdiving alone or 1v1ing people and they shouldn't ever be good at it.
Zed's ranked winrate is like 46% with 48% in diamond, he's nowhere close to being OP or even strong.