Mac M1 dual screen flicking on when display’s supposed to be sleeping

Hi,

A problem has started with the latest update that first existed years ago when I first got this M1 Mac mini. Using one screen plugged into HDMI and another ont he USB to DiaplayPort the display on the USB to DisplayPort flicks on every minute or so then goes back to sleep, when both displays are supposed to be sleeping. Annoying when I am trying to sleep and my Mac monitor keeps flicking on and off.

*Tried changing the USB port and same

*Tried changing from displays use seperate spaces to usi g same space.

*Format my entire Mac back to factory reset and installed latest Ventura OS.

*Tured off wake for network access.

*Turned off screen savers and notifications while sleeping.

Still keeps happening. The problem used to be there when I originally got it and went away after the first few updates but came back this week.