Glad it worked out for you.
That's a sweet build, how are the temps? Would've been difficult to air cool that. Nice work.
Did you have any more problems like described in the thread? As I understand your problem was resolved after changing MB to new one via retailer?
Did you check possibility of any contact electronic components in the socket area (for example, double capacitors) with waterblock details?
I have same problem only with Z590-I model. I tested my system in an open air stand. Combined it after that with custom watercooling system and system sometimes works fine especially first week but later mostly is rebooted due to power recycling.
I tried most common methods like to changle PSU, memory an others but with no luck.
But yesterday when I take off my waterblock I have been realized that waterblock body impacted and damaged 2 capacitors in the socket area.
I strongly recommend you to check out this moment. I think that soldering issue was reasoned by shirt circling and maybe is the real reason of the thread problem. It's dangerous. It may cause a fire.
For the ROG STRIX X570-I Gaming motherboard, the RTC CMOS battery is located on top of the group of ports just to the left of the Wi-Fi Antenna ports. It is packaged in shrink wrap and held there with strong two sided foam tape. Battery type is 3V Lithium CR2032 with 6.5cm long cable with Molex 51021 2pin female connector, pin one positive. Access the backside of the motherboard to remove 2 screws securing the back half of the VRM heatsink assembly. You may need to remove the board from the chassis to get at that. Then remove the NVME heatsink, VRM fan screen, and rear I/O top cover/bracket. Being careful not to damage the cable for the VRM fan, gently remove the top half of the VRM heatsink assembly. The RTC CMOS Battery is now visible. It's cable is taped down and the battery is in heat shrink package.