@Vadim_Peretokin , this is an issue with the AMD Linux driver provided by the kernel. It is not provided by Framework. You have a few choices… Supposedly the newer AMD drivers have fixes to alleviate this issue. So, you can wait for the kernel to get the latest driver version. Depending on the Linux flavor you use this can take a long time. Or another option is to roll your own kernel and bring in the latest AMD driver. But there isn’t much for Framework to do here.
Personally, I removed the external GPU on my Framework and that seemed to help. People also have turned off auto brightness settings which helps alot. There is also a way to mitigate the problem by resetting the driver when the issue pops up.