Really bad news for you...
It is a known fact (do a search on
X570 motherboards on YouTube posted by
Hardware Unboxed) that the
MSi Gaming Edge, Gaming Pro and the
A-Pro motherboards have probably the worst (i.e. cheapest) voltage regulator implementation of all the X570 boards (all three boards have the same VRM design, differing only in heat sink design), using only a 4+2 design (their
Gaming Pro Carbon (which i unfortunately have) is almost as bad with a 5+2 design). Their tests showed that the
Asus Prime X570P motherboard VRMs hit 66 degrees while the MSI A-Pro hit 115 degrees, almost 50 degrees hotter. The MSi board failed their testing by automatically and constantly throttling back the CPU.
Because of the crappy VRM, the MSi VRMs overheat reaching over 100 degrees C. That causes the CPU to thermal throttle, especially when you have a higher end AMD 3000 series CPU and more so when you try to overclock the CPU. Boards with better VRM designs normally run about 60-70 degrees which can handle the increased voltages when overclocking.
Sadly, the only way to get around your problem is to buy a different motherboard that has a better VRM design.