Yes, I am :D Yeah, it's a bigger trend there. Depending on the social and tech circle.
It's mostly about control, data privacy and sometimes about cost as well. Commercial services have feature creep, remove features, change prices, use your data and might vanish at any moment.

One theory why open-source in general is more popular in Germany that made it's round is that the standard of living is pretty high, especially for devs. So they have the time to work on open-source and self-hostable software.

And it's also fun :)