Really rough rule- DPI = dots per inch (like you said). It should mean less GPU and power to run lower DPI, and bigger text. But there is also the issue of DPI being partly invalidated by display types (like pentile), and marketing (the real evil).
I feel moving to UE5+ is going to help them immeasurably, the tools should speed up development and prevent about half of the issues we saw early in CP2077.