I only know German ones: senfcall.de or bbb.digitalcourage.de

the big ones out there are BigBlueButton and Jitsi. they have a lot of public instances, so you can easily check if they fit your needs.

Has a mobile app!

I use it daily for travel by bike or foot (kombined with BRouter). And its awsome!

Experiance by car is a bit mixed tho. (EU-Germany)

Stating foss and not even linking the source is … hmm

Nothing realy exept licencing

Maybe consider using forgejo (gitea fork used by codeberg)

And i do think, some changes would be needed but nothing big, also it wouldnt ne activated by default.

Ich nutze eigentlich nur noch firefox oder firefox derivate. Mainly aus überzeugung.

Ich habe noch ein backup chromium rum liegen aber der kommt nur sehr selten zum einsatz.

Habe mich vorher viel durch probiert (opera/vivaldi/etc) und vermisse eigentlich nur tab-stacking.

Zeichenlimit war glaube ~60chars ist mir auch passiert.

Nextcloud is selfhosted, yes. But managed solutions exists, so you dont have to set it up your self/maintain it. (Free instances seem to exist https://nextcloud.com/sign-up/ dont know about privacy/encryption on these tho)

I am using Nextcloud Calender + DavX5 (android) + etar (android) for my colaborative and synchronized calenders. Working good since 1 year.