I was not aware of this. All of my limited knowledge of the Mark comes from the Left Behind™ books that I read as a teenager. I know, I know, the Left Behind™ books are bad theology, but they were pretty entertaining reads as a 14 yo who was having dreams about the end of the world at least once a week.
I think that if a MotB is implemented, it will be some sort of a symbol or mark of allegiance to woke, social justice ideology that you get in order to show in no uncertain terms that you aren't a Christian. Granted I don't think it's going to be '666' or anything, but it will probably be an RFID chip implanted in your skin that Christians are not allowed to get or something.