@leocg I tried your suggestion, downloaded some popular one and switched to a few user agents like Vivaldi, Edge and different versions but it didn't seem to work. I tried 'User-Agent Switcher and Manager'.
It seems that nothing beside a fresh installation won't work.
Already cleared cookies, site files etc.
Or maybe I will just learn how to create a virtual machine and install Opera there to test stuff.
There was one time something worked, that I saw suggested: turn off Tracking Scripts Blocking (or whatever that option is called in English).
Once I did that, it worked. It was about 3 weeks ago but it stopped working very fast
