In Photoshop 2020 (21.1.0), the Legacy Undo while in Free Transform Mode does not work even after setting it up:
(window/Workspace/Keyboard Shortcuts & menus - Keyboard Shortcuts, click Use Legacy Undo Shortcuts)
Command + Z (Mac) still moves one step back in the undo chain.
Shift + Command + Z (Mac) does not work either.
Is there a way to set the Undo in Transform Mode to behave as Legacy Undo?