2015 Mazda 6 2.5L SkyActive (G, I think)(I'm seeing differences between timing marks and years of same generation) 137K miles

Crankshaft won't rotate either direction.
Breaker bar full force. Timing Chain, Camshafts, and Spark Plugs, removed. Also tried with removed Cylinder Head, anyway. I replaced the head gasket.
Valves are all closed and look fine, but removed anyway.
I don't see any lock peg anywhere on the crank case.
Starter Motor removed.
Car broke down in Drive gear, going very slow like 1mph, if that matters.
It needed a new timing chain because the guides were damaged from a leaking head gasket. It already had check engine codes for retarded camshaft and crankshaft correlation.
Was revving up and down in park/idle.Probably need to replace the Purge Valve (PE0118751).
Engine overheated a dozen times while I needed to work to survive and get just enough money to do any work on it between work. I kept changing the coolant and oil. I successfully used a coolant head gasket sealer.

My engine has the 2 timing marks on the crank sprocket. I have no information on the key-way being default upside down almost.
I did try to start it with the keyway perfectly lined up with the two color links and it did not crank at all.
Mazda's manual actually does show an illustration with the 2 dots and keyway turned up is correct. I can't find that anywhere, all videos show only one mark, which is confusion because the 2 marks are facing up as if they're representing the 4-2-1 exhaust and cylinder pairing as being top dead center with cylinders 2 and 3 at top.

My best guess is the crankshaft is locked/stuck in place because the transmission is holding it in Drive, if that even makes sense(I don't think so)
I wonder if Mazda would have an automatic safety feature if there's a peg(lockpin, peg thing) that engages the crankshaft to hold it in place to prevent damage.

This is my first post, I got pictures to add. we can make this thread a strong reference for anyone facing a stuck crankshaft issue in combination with leaking/ leaked to overheated issues.