The messages about not finding media, probably a bug and harmless. I have those messages as well after I remounted my hard drive at a different path. Let's start with turning off DLNA and see how things go.
Jellyfin 10.10.1 (Docker)
Ubuntu 24.04 LTS
Intel i3 12100
Intel Arc A380
OS drive - SK Hynix P41 1TB
Storage
3x WD Red Pro 6TB CMR in RAIDZ1 (JF Library)