Found an extremely useful utility for MacOS - "displayplacer" for MadMapper installations with several output devices, especially if they sometimes end up out of order, or the OS forgets rotation. (MadMapper usually handles this well if you've assigned the outputs, but I've had cases where it gets confused).
https://github.com/jakehilborn/displayplacer
"macOS command line utility to configure multi-display resolutions and arrangements"
simple to run to get the current display configuration (arrangement, rotations, etc...) and then be able to apply it back.
I then use an AppleScript after startup to apply the saved configuration (time delay after login to make sure all of the screens/projectors are recognized). Then startup Madmapper.
Using it with macOS as old as 10.14.x, and as new as macOS 15 (sequoia).
2018 Mac minis with eGPU, to M4 Mac mini's.