I've now gotten my third Asus Strix motherboard refunded. The first was a different model with Intel socket, but the last two were the same Strix x570-i model that you mention.
They all broke down at different stages. Which leads me to believe it's more BIOS related than hardware. The first Intel socket lasted about 4-6 months, the second never POST:ed and the third worked perhaps a few weeks to a month or two at most.
No confirmation or acknowledgement from Asus about what the problem is, they just issued the refund. So if it's poor manufacturing, BIOS problems or other thing I don't know. And no compensation for the extensive troubleshooting or pain it caused me.
All my components have been tested and working in other computers but I had to prove that every single time, which is time consuming. (But I do get why.)
So send it back and buy a new motherboard. I went with an different vendor this time that seems to be working.
I would have probably stayed with Asus if they just confirmed why this happened and how they're working to fix it.
Hope this helps and that it has caused you less suffering than it caused me.
I RMA one x570-i for a bad usb port, which worked fine besides that. I probably should have just kept it to be honest because the new x570-i I got kept freezing or going black screen when booting windows. Reinstalled windows, Cleared CMOS, tried to fix in safe mode. Nothing worked, just sent it to be RMA again. I hope the next one works, it can be a lottery honestly!