I have never had this issue with any other version of VEGAS or Movie Studio, but since updating to VEGAS 23 (Build 278), my preview is permanently flipped vertically, and the picture is dark.

For the darkness issue that is solved by simply moving the window to my SDR monitor, rather than my main HDR monitor, I'd still like to know how to fix the issue on my HDR monitor, since that's the one I want to use VEGAS.

The upside-down issue, on the other hand, I have absolutely no clue what's causing that or have even seen anything of this issue either on this community page or generally online, especially as said, the video is only flipped vertically, not horizontally too, so basically it's not properly upside down / rotated 180 degrees.