Display next date based on choice field

I have a multiple choice field that contains the name of weekdays called Days. I am looking for a solution to update the date field (Date) with the next time a Day is Monday or Tuesday and so on, which should be updated every day. I thought a simple if then statement could work but I can't seem to get it right. As I'm new to Ninox, I have no clue on how to get this to work