The only other explanation I have is that I was trying to connect Zed with Claude, so that redirected me to the Claude site, I registered an account and it said it needed a pro license, so I plugged in my CC details and off it went.

Upon returning the OAuth (or w/e auth it is) back to Zed; it logged me out and told me i was banned.

That's probably why. You're not allowed to use the subscription with any other coding harness other than Claude Code.