On the client you can manually select a lower bit rate. AFAIK, the client's won't detect that the connection is slow and adjust in real time. This would trigger a transcode, which we got setup properly now.
Jellyfin 10.10.6 (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)