Premiere Pro 2019 UI too small

Here is part of the problem:

Premiere Pro has an absolute minimum window size (meaning that the export window cannot be adjusted at all below a certain minimum size), and attempting to adjust the UI (which the only way to do would be to adjust Windows display scaling in the Windows display properties within the OS itself) in favor of larger text sizes may result in the monitor's effective resolution becoming too low for Premiere Pro, which means that parts of the UI will become completely hidden to the point where even exporting video will require multiple keyboard presses just to even retrieve the export button!

And that is due to the legacy code that's still remaining in Premiere Pro. The program wasn't really designed for high-DPI monitors to begin with. In fact, the Premiere UI assumes a monitor pitch of only about 100 to 150 ppi (this corresponds to a resolution of only 1080p for a 21.5" monitor). At the time that the Premiere Pro UI was last updated, most high-end PCs were still running a display resolution of only 1280x1024.