To show additional resolutions:
- Open the Displays system preference
- Find the preferences window for the screen you want to adjust
- If not already selected, choose the "Default for display" resolution setting
- While keeping the option (alt) key pressed, choose the "Scaled" resolution setting
The complete list of resolutions accepted by macOS should now be visible.
If you have a 4K display and text and windows are too small for you, you can choose the "1920x1080" mode from the list. This will set the display to the 4K retina resolution.