I have the same issue with this random auto dimming.
HDR on in windows 11 and in monitor, connected to RTX 3060 Ti Dp 1.4 on HP Omen 25L and when i open any window with white background the monitor stay bright for about 7-10 seconds, sometimes for few minutes and then dims itself by 30-40% and when i minimize the window and reopen it, the same thing happens, screen stays bright for few seconds and dims itself.
I’ve read the manual but no reasonable solution there about this issue. Same thing happens on 160 or 144Hz, my Nvidia drivers are the newest ones and so is windows. Anyone experienced this issue or has a solution? ACm is OFF, HDR is AUTO, Adaptive Dimming is Average (makes no difference in other modes), DDC is OFF, DSC is ON.
I've disabled that service but nothing changed. I cannot find the Auto brightness option in my Win11 either so i don't know if its the monitor or windows at this point..