I don’t know if this has been mentioned in another post or there is an option I have not found, but I have to look hard to see the underline below a misspelled word. It is just too subtle. I tried changing its color and even the Editor background color. It needs to be adjustable or simply thicker. I’d suggest just making it thicker and allow the user to dial back the intensity of the color until they are comfortable.
It was mentioned before somewhere and I agree. It should be more obvious somehow.
There is an option to change the underline style.
File > Options > Corrections > Underline style
For those having trouble finding it.