Simplifying Custom Formulas in Google Sheets

I wanna know if there is an easier way to do this. I have a custom calendar and there are 4 conditions for every day. You can see the example.

All those cells are colored based on a condition.

Yellow if I fill in "Overuren"

Blue if I fill in "Verlof"

Green if I fill in OK below "Di and 2" cell

Purple if I fill in Feestdag below "Di and 2" cell

While I got all that working, this means that I have 120 formulas for each month. Is there a way to combine all those formulas and make it simpler? Or if someone has a better idea I am all ears.