You also need to try a different monitor.
Edit: It is very important to try a monitor with HDMI or DP port without a converter adapter, because the new generation GPUs are configured for HDMI and DP compression.
The vast majority of problems you experience are most likely driver errors. I just wrote up the reason for the graphic distortion you shared and how you can fix it. In other words, you can solve the graphics problem you experience after 1 hour of gaming experience by lowering the GPU frequency with WattMan. The remaining problems are due to the game(s) and the driver(s).
CS-GO and COD issues are likely to be resolved by updates in the future. For this reason, I recommend you to use the latest Windows operating system and the latest driver.
Problems can be resolved by notifying AMD engineers with the game name(s), game setting(s) and all system information. So use this for notification... https://www.amd.com/en/support/contact-email-form