We went with notion and while it was kind of fine in the beginning the performance has degraded more and more. Sometimes things do not load at all or it takes forever.
What does notion do? Instead of fixing performance they work on Notion AI to make writing easier. Not sure how other people are using notion but I am never writing in full sentences or paragraphes anyway. It's a way to store notes and bullet points 90% of the time.
Anyway, most important for me is to have a way to create a kanban board. Discussions can happen async inside of the tickets which is a kind of documentation in its own.
What I have learned is to start with as little structure as possible. Most people don't ever look into notion or a wiki ever again and everything that's being put in there is basically dead in this moment. Even worse than no documentation is often wrong and outdated documentation.