I am using Symphony it's licensed under gplv3 and plays every audio format I throw at it. Also it has a basic, but beautiful ui. It also has a feature to make playlists
Really depends on how much of a niche the things you are looking for are. Content is quite easily to search with postman. As I personally don't really use private trackers I don't have a lot to compare to, but most torrents I have stumbled upon had a healthy amount of seeders on i2p
Have been using it for quite some time now and honestly I have found almost everything I searched for and once you set the router bandwidth properly, I was capable of downloading and seeding with 2MB/s. Satisfied my needs and gotta say not worrying about Letters coming to you is very calming
How about Mailcow? I mean you don't need to actually create the Mail Server in order to use Calendar. The setup is pretty straight forward
https://docs.mailcow.email/