For the moment
Pause and undo
Stop arranging for a while, or step back through what changed.
Show me how
Undo
Keyboard
Press ⌃⌥U. Press it again to go further back through your arrangements.
Mouse
Click Undo in the menu bar panel.
Pause
Keyboard
Press ⌃⌥P. Press it again to carry on.
Mouse
Turn on "Pause arranging" in the menu bar panel.
Stage Manager
Arranging pauses by itself while Stage Manager is on.
Turn one display off
Each display can be turned off from the menu bar panel, so Findow leaves it alone.