Haven't used Kodi but am running Jellyfin via the official docker image on a Raspberry Pi 4. Even there transcoding works reasonably well for one user at a time, admittedly didn't try with several users at the same time so far.
Just mentioning the docker image because I used to install it without docker directly via the repository and I never got transcoding to work on the same hardware.
Fantastic to have more selection! I love Findroid but its good to have alternatives!
Edit: downloaded it from Github but cannot connect to my server with same credentials I use in the official app, hm.
Edit2: OK, others have same issue https://github.com/fredrikburmester/streamyfin/issues/12
Edit3: they just released a fix
So I will test it again tonight when I have time.