So one of not-really-recent updates brought us the ability to change camera resolution via a config file. Unfortunately, the resolution is capped at a measly 4K. At the same time, newer GPUs can handle 8K without any significant issues.
Perhaps the limit can be removed from those config file entries?
Not to mention that on desktop pressing Ctrl+F12 while your resolution is set to 4K does produce 8K screenshots anyway.