Forgot password, can only access network screen on startup

So I created a new admin user to prep a MacBook to sell. Lo and behold I forgot the password I created, and now I can’t get into the laptop. I restarted in recovery mode, but it’s trying to link to an Apple ID from media I owned it, even though I was logged into it for a while. Now I can’t do anything but boot into the Choose Network dialog. It goes through the long online recovery, only to bring up the unknown user ID. Back to square one. I have a USB drive with Sequoia on it, but I can’t even boot from that. Is there a secret way to wipe this hard drive and start over?