https://www.mobile01.com/newsdetail/25112/pentax-k-1-markii
(in Traditional Chinese)
Handheld pixel resolution and high ISO settings are tested. The result pictures are self-explanatory with simple legends.
In short, the handheld pixel resolution is a hit-n-miss game, I'm afraid. Sometimes, the outcome would be even worse. Besides, the improvement at high ISO values is not really significant. Subtle improvement could be seen, though, IMHO.