Long story short: completely stripper the hex slot on the back of the freehub body while trying to remove it. It’s incredibly tight. Can I just take a pipe wrench to it from the front or do the teeth seen here on the new part lock with the wheel hub making it impossible to turn?
I’ve managed to take out stripped allen bolts with a torx bit before.
You centre it and bang it in with a mallet and hope to hell there’s enough holding on to turn the stripped one out.