If the 38 got into a flat spin wouldn’t cutting 1 engine off help you recover?
I believe it would stop the spin but you'd still drop straight down. It also helps you rotate a hammerhead. When stalled after a zoom climb you can point the nose anywhere you like.
I made a video about asymmetrical thrust in the AH P-38 if you haven't seen it you can click my youtube link.
There was a really good aviation historian who died flying a P-38 when one engine cut out on him. His name was Jeff Ethell. This was in the late 90s, always enjoyed watching him on "Wings".
He was friends with my dad when they both lived in Virginia. I never met him but I have two of his books, one that he signed and his Komet book signed by Rudy Opitz.
Ethell describes using asymmetrical thrust in the coverleaf maneuver, something he heard about from his dad, a P-38 pilot. The description sounds like he's rotating the yaw axis when he gets slow enough at the top of an oblique hammerhead. Doing this 4 times makes a 4 leaf clover if I understand it correctly.