Ah yes, if your laptop is non-hidpi and your display is, you will have these issues. In my case both the laptop and the display are hidpi, and things work pretty well. Basically all devices I used in the last decade are hidpi.
My laptop has a 14 inch 1080p display which is ~157 PPI so it needs around 1.2x scaling. My external monitor is 27 inch 4K which is ~163 PPI so it needs at least 1.5x scaling.
The most obvious solution that fixes all of these problems is to buy displays that work with 2x scaling. A combination of 15 inch 4K or 13 inch 3000x2000 laptop display and a 27 inch 5K external display is the ideal combination because both of them would work with 2x scaling.
