I posted in another thread about this issue, and it does seem to absolutely be a High DPI Scaling issue in Windows 10. Setting the scaling to my monitor to 100% and rebooting my computer, the UI looked just fine, and when I scaled everything back to 150%, and rebooted, the UI looked messed up again.
To fix it temporarily,
Open Task Manager and kill the "Enpass Password Manager" application running in the background.
Scale your display to 100% in Display Settings
Scale your display back to whatever scaling you had set previously.
This will only last for your current Windows session, but should make the application usable.