The best method I’ve found yet for rusted fastener unsticking is massive doses of vibration. A big ball peen with some forceful blows as close to the stuck thing as you can get.
That mayhew “bolt breaker” with an air hammer can work magic.
Here's hoping MY random penetrating oil recipe works well. I finally found a supposedly good 2WD E4OD for my 96 F250, and before I get started on pulling the old transmission out I soaked all the exhaust bolts with my own concoction of the dregs of several cans of WD40 and PB Blaster that had run out of propellant, 3 or 4 ounces of Marvel Mystery Oil and several ounces of acetone.