Also check "only generate images from key frames". Generating trickplays will happen MUCH quicker when that is enabled. The small loss in timing accuracy is worth it, IMO.
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