Debian is really easy to install now. It used to be much harder back in the day.
I host a Lemmy instance at https://lemmy.buzz
My other Lemmy accounts:
https://lemmy.buzz/u/HorseFD
https://lemmy.ml/u/HorseFD
My Mastodon account:
https://mastodon.world/@HorseFD
Debian is really easy to install now. It used to be much harder back in the day.
Posteo is in fact open source.