Hard to say.
Kyrie has had knee problems before and now he’s dealing with another surgery.
It’s likely to get worse and that will eventually reduce his explosiveness. He will still be good but he probably won’t be better.
I’m betting he’ll get hurt again with the Celtics. Boston will still be ECF contenders with him tho.
Hayward should be fine.
Though he kinda seems redundant with the way Brown and Tatum are developing. I could see the Celtics putting out trade feelers for Hayward. Yeah he’s better than Tatum now. And depth matters, so having them both is a great problem to have. But that 4th year is a player option and I don’t see any way Hayward declines it. I also don’t see any way Boston will want to pay it.
Boston has a 2 year window before they have some difficult decisions to make.