Same location as the transcoding settings. Settings > Dashboard > Playback. About halfway down the page. "Enable Tone Mapping", a bit further down from "Enable VPP 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