does all your settings are saved correctly? And did you restart your system afterwards?
As well you would need to create a pkcs12 file. I found this one and on my test it is working https://gist.github.com/novemberborn/4eb91b0d166c27c2fcd4#gistcomment-2593153
root@DietPi4:/etc/jellyfin# ss -tulpn | grep jelly
udp UNCONN 0 0 0.0.0.0:7359 0.0.0.0:* users:(("jellyfin",pid=15203,fd=308))
tcp LISTEN 0 512 0.0.0.0:8920 0.0.0.0:* users:(("jellyfin",pid=15203,fd=292))
tcp LISTEN 0 512 0.0.0.0:8096 0.0.0.0:* users:(("jellyfin",pid=15203,fd=288))
root@DietPi4:/etc/jellyfin#
But this would need to be done again each time you receive a new certificate. Means you would need to create a script that will be executed by certbot once a new certificate was created.