If you rename it using your BitTorrent client, it should still seed fine.
If you’re on Linux, a better option in my opinion, is to make a symlink to your Jellyfin folder and rename the link. The torrent client will see the original filename. Jellyfin will see the new filename.
In my case, I’ll move the finished file to my Jellyfin library (since that’s what my backup software points to). I copy the original filename temporarily. I rename the original file how I like it. Then I make the symlink into the folder I’m seeding from. I then rename the link to match the original filename.
If I’m training my NI (natural intelligence), that’s fair use, right?