The word "Messiah" is an English rendering of the Hebrew word Mashiach, which means "anointed." It usually refers to a person initiated into God's service by being anointed with oil.
(Exodus 29:7, 1-Kings , 2-Kings 9:3) What is the Messiah supposed to accomplish?
This also relies on Mark being the person mentioned in Acts and 1 Peter. Second, the name Mark was just a later addition to the gospel, which again is anonymous.
We simply have no reason to think this name is actually the name of the author.
The arguments for these claims go nowhere and rely on circular logic.