Oh, did Nero cause everyone to have a mark on their hand or forehead? Must have missed that.
Interpret the Bible with the Bible. What’s literal and what’s figurative in Scripture is easy to understand if the Bible is the standard and not our own modern ideas.
The “mark” on the forehead is referenced in the Old Testament. Back then Jerusalem was about to be destroyed and Ezekiel 9:3-6 speaks of an angel placing a mark on the forehead of those who lament the wickedness of the city. The context was not that a physical mark would be placed on them but this was a way to illustrate that when the city was destroyed some would be preserved as a remnant.
1st century Christians would have recognized this reference to a “mark” and would have understood the meaning in reference to a remnant who would be preserved.