Someone I haven’t seen in roughly 6 years found my private account

For context, my private instagram account does not have my name anywhere on it (display name or username). A few months ago I got a follow request from an account with the same full name as one of my teammates from a soccer club I used to play in. I had moved to a completely different state 4 years ago so I found this follow request strange, especially since the account had zero posts. I went through his followers and they were all names of people that I vaguely recognized as old classmates of mine, so the account seemed like it was legit the same kid I knew from 6 years ago. I accepted the request and followed the account back, thinking maybe I would get an explanation as to why he followed me, or how he found me, but to this day he hasn’t reached out or posted anything. I’m really confused as to how he managed to find me or if it was an accident, since as I mentioned before, I don’t have my real name anywhere on my profile, only a nickname that I got a couple years back so there would be no way that he could’ve known it was me. Additionally, my profile photo doesn’t have me in it at all so he couldn’t have seen it was me and sent me a follow. We didn’t have each other’s phone numbers either so it couldn’t have been the contacts app exposing me. I thought that maybe he followed me on accident but the only people he follows all seem to live relatively close to where he lives, based off of their bios. We also have zero mutuals so I’m really at a loss. I know the best idea would be to reach out but I have no idea if he even uses that account since his last (and only) repost was from a year ago.

TLDR; old soccer teammate requested to follow me on instagram even though there was no way he could’ve known it was me