Asalam ul laykum brother, from what I gather about the mark of the beast refers to satan and anti-Christ. It is some Christians who like to play around with words and come up with conjectures that think that it talks about the same beast that is mentioned that will rise out of earth. Now, here are some verses from the bible I gather that are more clear in understanding of what the "beast" is, if you compare it with Quran. It is clear it is a prediction of the future coming of the anti-Christ.
Revelation 14:9-11 "And another angel, a third, followed them, saying with a loud voice, “If anyone worships the beast and its image and receives a mark on his forehead or on his hand, he also will drink the wine of God's wrath, poured full strength into the cup of his anger, and he will be tormented with fire and sulfur in the presence of the holy angels and in the presence of the Lamb. And the smoke of their torment goes up forever and ever, and they have no rest, day or night, these worshipers of the beast and its image, and whoever receives the mark of its name.” "
See how it says "forehead" and mentions that "He will be tormented with fire and sulfur in presence of the holy angels and in presence of the "Lamb"(referring to jesus pbuh)" this is a future prediction that are supported by quran that will happen that Dajjal(anti-Christ) will have a mark on his head which will say Kaffir and when jesus pbuh will come he will die.
Revelation 20:4 "Then I saw thrones, and seated on them were those to whom the authority to judge was committed. Also I saw the souls of those who had been beheaded for the testimony of Jesus and for the word of God, and those who had not worshiped the beast or its image and had not received its mark on their foreheads or their hands. They came to life and reigned with Christ for a thousand years."
this is about the golden age after dajjal dies. Remember Quran was sent to confirm and complete. Even though bible is not injel and gospel is not injel, there are some parts that still exist, however many parts might have a bit of truth but also contain conjectures that make them a bit hazy.