M1 Pro MacBook Pro drives Thunderbolt Cinema Display at Half Brightness

Hello everyone,

I am at a loss, and I am seeing advice/questioning if anyone else has this setup. I have a 21 MacBook Pro 16" with the M1 Pro, and when using a TB 3 -> Adapter, my Thunderbolt Cinema Display will only go up to half brightness (I have maxed out the brightness in settings, and turned off the auto adjust and all that).

At first, I thought it was a problem with the cable, since it is old and kind of fraying. I bought a new TB 2 cable at expense to test that, using the female port in the back. No change.

At this point, I thought the monitor itself was screwed, but after quickly testing it with my 2015 MBA and having it work fine, it seems to be either an M1 thing or an adapter thing.

Before I RMA this adapter to Amazon (which I should do), I am writing you all to ask, does anyone have this same setup? If so, does it work fine? Should I try to find some other way to connect to this monitor?

Just so you do know, I have tried BetterMonitor, Lunar, and MonitorControl to try to force the brightness higher, but even after maxing it out in those apps, I have seen no difference.

Many thanks,

-Herc