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
Pretty sure there is an unofficial flatpak for makemkv
Proton only allows port forwarding on their paid tiers, and you still need to enable it and select a server that allows port forwarding.
I would simply use something a little less fishy and cheaper AirVpn you can pair over there also with montero and some other crypto