If you have tried several self-hosting platforms like the above, please share your experience.

I have so far only tried Yunohost and I'm quite satisfied. It does help to read French, sometimes solutions can be hidden in French forum topics.

Coop Cloud seems to be docker-based, as far as I understand, and I just never managed to wrap my head around containers and why I should use them. Not sure though if Yunohost does container stuff in the background that I am not aware of?

I've just started to use my Yunohost installation for some small scale collaborative stuff so I really hope it scales (to probably not more than 100 users) and keeps running smoothly. Starting to host common stuff is a little more scary than just fucking up my own private files.