No contact is a tool, not a rule. It's a tool we use to detach, but it's only one of them available to us, and some say limited contact is actually better and less stressful. Bottom line, what ever works for you, making your health and wellbeing the number one priority.
I don't think it's black and white either.
I think you know the answer that there's a probability you may not get validation newtothis28.
I was surprised my ex wished me a happy birthday this year two years after the break-up and I said thanks.
I wished her a happy birthday too and wasn't validated and didn't have hopes that she would.
I also maintain low contact.
I don't think there's a right or wrong with NC and above all take care of your needs first. If it's upsetting and triggering, likely not a good idea and there's always the next one