First off, best of luck, I have an XFX RX 5700 that has never worked right. I get random crashes, freezes, driver timeouts, etc since adding that card. I figured that surely, there would be a driver fix or I'd be able to figure out what was causing it. Nope. I work in tech support and know what I'm doing and I've spent countless hours trying to fix it, researching the issue, learning about extremely obscure software settings and hardware parameters (on top of all the ones I already knew) and it's still busted. Here I am still trying to fix it years later. I really regret not returning or RMA'ing it.
There's a million things it could be and you could try them all and it still might not work. I don't have time to walk you through everything, but I'd figure out now how much time you really want to spend on this because the rabbit hole is deep. There does appear to just be something glitchy with AMD hardware/drivers and certain multi-monitor setups, they've stated this in driver patch notes, without saying exactly what that is. Maybe because they don't really know, I'm not sure.
From what I gather there are problems with certain combinations of monitors, particularly with different resolutions and refresh rates, and the way the Windows Display architecture interacts with them, that causes complications for video cards and drivers. I'm not saying that's your issue, but it could be, and if so it might not be a quick fix, or be fixable at all.
One thing I have seen people say seemed to fix this kind of issue, specifically on those MSI B450 motherboards, is going into the BIOS and changing the PCIE slot version to PCIE 3, instead of AUTO. I don't know why this matters, it should work fine on AUTO, but I've seen multiple people say this resolved their issue. That's the first thing I'd try.
I've seen some people say disabling ULPS (by changing registry keys) fixed their crashing issue after nothing else did. Again, not sure why this works, it shouldn't matter, but obviously there's some compatibility issue on certain systems. But it's another easy setting to change so worth a try before you get too deep elsewhere. Just google it.
But it could be something more conventional, here's some other basic stuff to consider:
Everyone will tell you to first do a clean driver install. There's an option for it in the driver install dialogue itself, or AMD has a "AMD Cleanup Utility", but I'd probably opt to download the software "DDU" as it's probably the most comprehensive and will uninstall any extraneous video related drivers that exist on yours sytem. There are instructions on how to do this all over the place, just google "DDU instructions". Before you do the clean up, download the video drivers that you're going to want to install later.
Cables & Connectors - Even if it's "working", sometimes a video cable or video connector or adapter can be an issue. Maybe there's something wrong with it, maybe it's poor quality, a bad connection, maybe it's an old HDMI 1.0 cable and doesn't support the newer, faster standards, or whatever, but cable issues can cause communication/signal problems which could cause crashes. It's worth swapping out with other cables you might have around just to test, or buying some verified "good" quality cables. There are some lists of higher quality cable vendors online, these aren't expensive, just some vendors make better quality products than others.
Don't rule out your Power Supply as a potential culprit. Even if it's technically powerful enough, at 550 watts and only 80% efficiency, it's really only supplying 440 watts and that is getting really close to what your system might need to run under load. Just the parts you listed shows as 424W when I add them all to PC Part Picker, which doesn't account for anything else plugged in (keyboards, mice, webcam, wifi, extra lights and fans, etc.), so it could be maxed out. The other thing to consider is the quality of the power supply. Some models and vendors are more reliable. I don't know about your particular model, but I've seen another discussion about a similar crashing problem and someone pointed them to a review of their EVGA power supply showing that it tested as having inconsistent voltage on some cables, which could definitely cause crashing. And just a note - If you do swap out for another power supply, don't just use the existing power supply cables that are in your system, they're not necessarily compatible. Different power supplies can have different pin configurations for the cables and connectors. Always use the cables that came with the power supply to ensure compatibility, otherwise it might not work, or worse, you may cause damage to some of your components.
That's all I got in me for now, whew, good luck on your search!
