Oof. If /dev/sdb is, in fact, the drive you took out of your Windows PC all your data is probably gone. It would have been NTFS before. But it is EXT4 now. Which means at some point you reformatted the drive.
Jellyfin 10.10.3 (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)