What settings did you use? Can you share screenshots of Dashboard > Playback? CPU usage isn't unusual if the audio needs to be transcoded. As long as the video transcoding is being offloaded to the iGPU.
Jellyfin 10.10.7 (Docker)
Ubuntu 24.04.2 LTS w/HWE
Intel i3 12100
Intel Arc A380
OS drive - SK Hynix P41 1TB
Storage
4x WD Red Pro 6TB CMR in RAIDZ1