Had the same exact issue - upgrade BIOS. You need to download from ASRock, write to USB, and follow instructions using the button on motherboard since no display.
Buildapc
Your board has a debugging code at the bottom, do they light up?
If they do, you can find the number in the manual
If they don't light up, then I'd assume the board isn't getting power, try removing the mobo from the case and check if you've got any case standoffs in places where they'd touch the mobo.
Your CPU has integrated graphics, so while the motherboard's out try testing it with just the CPU, RAM and PSU.
If it still doesn't work you might have to try using a different mobo / try and get an RMA on your current.
I had something like this once, in that case it was front io connected to wrong pins on motherboard.
Reseated them again and made sure they were all facing the same way now, per the book, and still nothin
edit: you waited hours, nevermind. But fyi-
Is it doing the ddr5 training?
https://hardforum.com/threads/long-boot-time-for-am5-normal.2034383/
On the off chance your front io buttons are broken, try bridging the contacts with a screwdriver?
Also, you may want to test your PSU by bridging the green wire to black, on the large 20 pin connector (disconnect first to be safe)
The board has a power button on it as well that also doesn't respond, the RGB and buttons on the board light up though nothin
Pretty unlikely that the board button and the case button are both broken, you may have a brick on your hands.
Worth testing the PSU anyway, in case only one of the voltages is broken. But you'll need a multimeter.
Are you sure you used the right number of standoffs underneigth? No shorts or anything?