I had similar issues. I think it was down to the immature usb and pcie4 drivers. I had to upgrade the bios on the motherboard, upgrade the usb drivers too, then enable pcie4 and the variable bar stuff in the bios. Only now in the last month have I had a system that runs stably in pcie4 config.
Am running an Msi x570 tomahawk, ryzen 5600x, 32Gb 3600 MHz RAM, RX6900xt, Corsair mp600 pcie4 drives.
Had to run it in pcie3 mode till msi updated the bios on the Moro to turn in pcie4 and for it to run without the temp freezes followed by really low FPS.
Before any words of wisdom on the match of components. It was 2020 I bought what I could get.