Inspiron 5675, AMD Radeon RX 570, Video crashing

I purchased a new Inspiron 5675 on Black Friday, specifically, the Inspiron DT 5675 with AMD Ryzen 7 1700X and AMD Radeon RX 570.

I immediately started getting problems with video glitches and, most frequently, the video suddenly freezing, going to black, and then coming back to normal after a few seconds. This would happen when I just browsing the web, and didn't seem to happen when I was playing a game, so it didn't seem to be related to the card being overworked or overheated or anything of that nature.

I tried messing around with drivers, completely wiping them and reinstalling, trying older drivers, etc, no luck. Made sure all the windows updates were installed, didn't matter. Figured I got a lemon with a bad graphics card. As I got a great deal on the computer and like the specs, I sent it for a replacement.

Now the replacement has arrived and, to my amazement, it is having very similar issues. Instead of simply freezing, it will suddenly have glitched out checkered boxes covering the screen and then either go back to normal after a few seconds or go black and then come back. Like the last one, this happens when I'm browsing the web, looking at photos, etc. Again, tried messing with drivers, doesn't seem to matter. I downloaded a temperature monitor of the GPU, temperature is fine.

I tried the monitor on another computer to rule that out. Not the monitor.

Is it possible that I got two lemons in a row here? Incredibly frustrating. Appreciate any suggestions. If I can't solve the problem today I will just get a refund and wipe my hands of it.