Pi 400 + hyperpixel4 = blank

Curious if it’s a known issue or just my own user error… Iv lost count on how many times iv flashed a new rpi OS, follow the one line install or github repo manuel install and each try after a few minutes the display goes black. This doesn’t accure when I replicate the install on a pi 4 though. All help is appreciated,
Thank you.

Same thing is happening to me, but it’s more like a few seconds after starting up. My desktop loads, then 1 second later it blanks.