You skipped a step where you put a cheater pipe on the breaker bar.

Torque vs deleting the object.

Heat around the bolt then rub wax which melts and wicks into the threads

Get away with that lousy torch…

There's a point in that process where you stop caring if you permanently damage things.

I had a bike where the stem of the seat was somehow permanently welded into the tube. Nothing I did worked. I took it to a bike shop and they said there was nothing they could do without damaging the bike. At some point I just gave up and was willing to sacrifice the bike's frame just to get those two metal parts apart.