Depends. Can you share an ffmpeg log with us? As long as you properly enabled hardware acceleration, your GPU should be more than capable to keep up with 4K HDR transcoding and tone mapping.
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