This is admittedly an area where we don't perform that well and is something we are actively working to improve. In the meantime, I can suggest something to try:
When you changed the screen resolution, did you also change the Windows Scaling setting? At 3200x1800 your display probably was probably set to 200% scaling by default. Windows is probably still scaling the text larger to account for the higher resolution you were using previously. In control panel, go to Control\All Control Panel Items\Display and set the size of text and other items on the screen to a lower setting (100% or 150% instead of 200%). Windows will make you log off to apply the settings. Try to match the scale factor with the resolution, for instance if you set the resolution down to 1600x900 then set the scaling to 100%.
Also, within SOLIDWORKS what button size are you using?
Give the scaling change a try and let me know what happens. Feel free to include a screen-shot or two as well.