Years ago.. when I locked up a Porsche 944.. had to pull the pan and loosen all the main bearing caps to get a crank to turn so I could undo the torque tube coupler... THAT was a big job.
maybe pull the pan and loosen things up? should turn eventually.
I have the pan off...even that was interesting as the pan is pretty much glued to the windage tray and the oil pickup is bolted thru the tray to the pump ( still new at these Gen III's).
Got to take off the damper, got the main cap bolts out but I still have to remove the front cover. Then I can unbolt the convertor from the flywheel.
Might even have a stuck camshaft if everything seized.