@MadMinstrel Not sure if you've tried this as well, but this is my 4K set up when I have Windows set to 200% DPI scaling:
1. Open the Start menu and type 'Mouse'
2. Select the 'Mouse Settings' option from the Control Panel section.
3. In the 'Pointers' tab, set the Scheme to 'Windows Default (extra-large) (system scheme)'
4. In the 'Pointer Options' tab, disable 'Display pointer trails' and 'Hide pointer while typing'. Press OK.
The mouse cursor might look weird and messed up at first, but after I restarted my PC the scaling was all normal again.