I have a brand new 16" MBP M2 Max 2023, which just replaced a 16" MBP Intel 2019.
I used Migration Assistant to move into the new MBP.
I connected my two Pegasus32 R4 the same way as I did on the old MBP, which is via two separate Thunderbolt cables, directly into Thunderbolt jacks on the MBP.
I have a large display in Picture-By-Picture mode presenting two separate DisplayPort conections, one to each Promise Array (e.g. each array carries one Thunderbolt -> DisplayPort connection).
With the new MBP, my external displays no longer sleep when the Mac is set to blank them, nor do the displays sleep when the MBP is actually asleep nor when the MPB is completely shut down. I can still see the LED backlighting is on and my power meter shows that the display is drawing 80 watts.
Everything else is fine w.r.t. power management of the arrays, it's just that the display is not being told to go to sleep when called for.
One change that I made in conjunction with moving to the new MBP is that I first upgraded the FW on the two Pegasus32 R4's to the latest version.
So I can't be certain if the displays not power-saving is due to the change in MBP hardware or the change in Pegasus FW. :-/
P.S. I can see a Pegasus32 category with a test message, but when posting this message the I don't see it. Nearest is Pegasus 3. Admin feel free to move my message.