Gary, I found the default too small even for my non-4k monitor.

I was working in milliPoints for a project and ended up with Point: 10pt (13.33px) and Line 6pt (8px).

The one thing I don't now like is the snap too readily occurs at the right and bottom page edges where I usually have a clutch of objects.
There is no Lock Page Size command or icon.

Acorn