Cryptpad? Or if you are up for a learning journey you could set up NextCloud and Collabora.
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Nextcloud AIO will help here, although you still need to be tech savvy
For the docs part, Proton has an alternative built into Proton Drive that is directly aimed at Google Docs. I can also recommend Cryptee, which can work fully offline and is completely web-based.
etherpad kinda seemed nice, never used it much tho
You can have a look at Docs
It's developed by the French and German government with the goal of replacing google docs for governments workers.
German center for digital sovereignty (ZenDiS) is working on an office solution for the German administration called Open Desk.
If you are already using MD, perhaps you like to try Obsidian.
Obsidian is proprietary, but I'll look into Open Desk.
Joplin is a decent FOSS alternative to Obsidian
I like Joplin, but it is a note taker not an office suite. So kind of depends on what you want.
You can just use LibreOffice. On Android the app I have is Collabora. The server I use is Nextcloud though it could be anything that LibreOffice and Collabora can work with. I think there is also some sort of web version too of LibreOffice, but I've never tried it. Maybe called "LibreOffice Online"?