Your other option is to configure Jellyfin to write logs to a non-standard directory and that directory is a mapped volume on both nginx and jellyfin. Or symlinks.
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)