This tip might help someone. I was having a similar issue with a PG329Q monitor and I've found that if I turn on the screen and immediately turn on the PC the BIOS will complain but if I wait for the screen to show 'Displayport no signal' and then turn on the PC there will be no issue and the BIOS splash screen will show and go straight into windows.
Hello, do you think the problem might be the BIOS? Which motherboard / chipset are you using?
I think it may be a combination of BIOS and monitor. The monitor could be not ready to respond in the way the BIOS is expecting at the right moment so waiting for the screen to finish looking for one type of signal can help. That said you would think they would have tested the Asus screen with a range of Asus motherboards including the one I have. My motherboard is an ASUS X470 Prime.
same problem with 2x ROG Swift PG32UQ, Gigabyte 3080 Ti MASTER 12G and ROG Zenith II Extreme Alpha with AMD 3960X.
both monitors connected with HDMI 2.1.
2nd Monitor also allways turn on/off few seconds random.
i also contacted support to update product side with firmware v026 for downloading.