I was just over at LibreWolf looking for possibly something to patch the HTML hole. But first I went to my google apps and I gave youtube the finger. No more youtube on my phone. Fuck you google! I am Loops all the way (LOL I gotta watch some shit, not gonna go cold turkey!)
My calendar is now on Thunderbird, which has an excellent desktop and mobile app as well.
I’m having good luck replacing document editors with onlyoffice, Although many people will recommend Colabora (with LibreOffice on desktop)
Edit: and Organic Maps, depending on how complete OpenStreetMap is in your area.
One of those has a network version of libre office so you can dockerize it and serve it from your central server.
You can run either one from a server or locally. LibreOffice allows realtime collaboration in spreadsheets only. OnlyOffice I think allows it in all programs. Both have web editors. Both work with Nextcloud /OwnCloud. It depends on what you want to do with your server.