mee seek and destroy…what’s is my purpose again?

+1 on this. it look easy from outsider perspective until you are in that shoe and feel how much courage/skill it need to say no.

what kind of tree is this?

you may try this: 1/make sure jellyfin is actually running and there is no error in logs and firewall is not blocking inbound connections

2/double check LAN IP/port jellyfin service running on and make sure the device you want to connecting to jellyfin can reach that IP (simple icmp ping is a good start)

try ungoogled-chromium

you can use agent switcher from firefox add-on and change your agent to chrome browser or whatever you like.