2018 MBP Still linked to previous owner’s FindMy, how do I reset?

I bought a 2018 MacBook Pro (intel) off of a guy on Facebook Marketplace in 2021. I’m now trying to sell the thing to cover urgent bills but when I tried to reset it via the settings it prompted me to enter the original owner’s Apple ID password to disable FindMy. I emailed him and tried to bug him on Facebook but he hasn’t responded. I wiped the disc with Disc Recovery but I’m struggling to get it to boot into Internet Recovery to try to reinstall OS and hopefully fully reset it. Is it locked down because it’s still attached to his FindMy? My Apple ID is attached to everything else on the computer. Not sure how to fix it.