You can use the Apps Script
Geocoder class to geocode addresses - the responses may include a plus code. If they don't, you can either use the add-on to convert the locations to a plus code, or, you can use the
reverseGeocode method of the Geocode class to get the plus code address. I've put together an example for you.
You can paste the code below into an Apps Script (from a sheet, select Tools > Script Editor). Once you've done that, you can use it like this:
It will return the formatted street address and the plus code addresses into your sheet like this:
Let us know if this works for you! Here's the code: