I have a 14" 2560x1600 USB-C portable monitor made by Zsus that I've been using successfully with my MacBook Pro M3 for several months. I mainly use it during presentations as a local mirror of what's going out the HDMI port to a projector, which usually means it's running at 1920x1080 HD resolution, scaled to fit the screen.

I was looking at the options available in BetterDisplay and thought that instead of running it in the native HD mode, I could use an HiDPI mode to render the HD mode a little more cleanly on my local copy (i.e. get macOS to render the 1920 pixels at HiDPI 2560, rather than sending a pre-downgraded signal to the monitor).

After a few clicks, the screen went blank. Plugging and unplugging didn't help, nor did rebooting, nor did uninstalling and reinstalling BetterDisplay. The screen powers up and displays a plain blue screen, and I can bring up an input selector on it (using its built-in controls). Meanwhile on macOS, it doesn't appear at all in the displays panel, nor in BetterDisplay, nor in the USB device list in the System Information app.

I was wondering if the mode selected through BD is causing the monitor's controller to crash as soon as it's plugged in, and that macOS is remembering this troublesome resolution whenever it's plugged in, causing it to recur. It's at this point I was wondering if there's some way of clearing this saved information, in the old "zap PRAM" style.

To track it down further, I bought another portable monitor (a different model), and that works fine on my MacBook. The Zsus monitor still works when plugged into a Mac Mini (which has never had that resolution tweak attempted), suggesting that this is a software problem on my MacBook, and not a physical problem with the monitor.

So, is it likely that this problem was caused by BD, and either way, is there some way this could be fixed by resetting something?