That’s likely a kernel issue. Happened to me also like a year ago. After updating to the latest kernel I have not had any problems.
Could also be that the card is not staying in the pci-e slot or is sagging as I have seen this happen often with heavier cards. It causes black screen, instability and performance issues in general.
As far as I know Mint and if things have not changed lately then Pop_OS as well has old kernel. Use distro with up to date kernel. For gaming a rolling release is usually a good option as the performance updates arrive early.
Where in the EU do you live? That price sounds so insane that I must check it out.