IF Statement needed to change cell value based on input of another cell

Hello - I'll openly admit IF statements are still a learning curve for me so any help is appreciated, this is sort of an extension of a prior post I had presented.

I have a Due Date column which is manually input by the user.

Based upon this date, the Due Date timer starts a countdown using =A3-Today(), once the item hits 10 or less days conditional formatting turns it yellow, 5 or less days turns red.

Currently I am using a formula that when an entry is put in Completion Date the conditional formatting stops and the cell returns to no fill =IF(A3="","",A3-TODAY())

Ideally I would like Column B to not display negative days even if it has changed colors due to being completed. Any ideas on a formula I could use to have Column B - due date timer change from a countdown to either "Completed" or just completely blank, no data if a Completion Date has been entered?

Any help is much appreciated and I'm always happy to give kudos to those who solve my issue.