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.
hiajen
every provider who supports aliases. like [email protected] where everything after the + is exchangeable. so you can use a 'different' mail for every service you use and just block where spam comes from via the alias.
Damm i read ABP ... and was confused. Yeh sure ads are smoll brain! (Same as ABP)
ADS?
Matrix i guess, its a federated messaging protocoll. Flagship messenger app would be Element. Sending large files would depend on the server you are on.
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)
I lost THE GAME
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.
I only know German ones: senfcall.de or bbb.digitalcourage.de