They say "barely lacks any features" which I think they mean it's full featured. I feel like Transmission and rTorrent are good clients for their niche though.

It’s just using cloudflare. So likely your private data is just temporarily stored on the CloudFlare node in your region and in Germany.

Use a bot account to post if you are worried

I don’t think necessarily have a few large instances is problematic. It’s fine as long as people can move to other instances, the issue would be if those instances leverage their size to force incompatibilities or defederation.

Makes sense just thought you might have had a hairpin setup through your router.

Is that IP address the address of your router that was given by the ISP router or is it the IP of the jellyfin server?