Code 43 on AMD graphics card

Hello,
about 10 days ago, I built my first PC, but there's a problem: I get the code 43 (Windows has stopped this device because it has problems) showing up on my AMD graphics card!

Here’s a summary of my setup:
- Ryzen 3 2200G
- AMD RX 570 8GB Nitro + (bought second-hand on Ebay)
- Gigabyte B450M DS3H
- Cooler Master 550W power supply
(I'll provide the rest if needed)

I should mention that the screen is connected to the graphics card with an HDMI to DVI cable.

Here’s what I’ve tried so far:
- I have changed the graphics card driver several times
- I updated the BIOS
- I unplugged the power supply and then started the PC to sort of clean it
- I switched the PCI on the graphics card (don't ask me why! :) )
- I disabled/reactivated my graphics card

And here I am, I admit I'm out of ideas and I'm starting to despair...
So if anyone could help me solve my problem, that would be really nice, thanks in advance!