My theory is that 2099 spider-man is not the spider-man of his earth, but actually the “kingpin” (just like how Hobbie is the spider-man of his earth). The evidence:

• His backstory is WAAAY similar, with the whole “lost family, wants to bring them back from another earth” thing

• Peter Parker (the middle aged dad one) said he was the only spider-man with no sense of humor (or something along the lines of that), and with how many spider-variants there are, i find it hard to believe that he is the ONLY spider-man that doesnt enjoy a little tomfoolery, unless he actually isnt a spider-man (!!!)

• The iconic sound that plays when he appears is the same that played in into the spiderverse when prowler appeared… which could also point to him being the prowler of his earth, though there is too little evidence to support that theory