I compiled a build that worked, but the number input fields in the various plugins display black text on a black background, so they're not visible. In the AppImage, however, the text is visible as usual because it's white. Could this be due to Arch's fontconfig, which is version 2.18.3?
Another problem: My Arch system has OpenCV 5. These aren't recognized during compilation:

"optional opencv4 not found: the OpenCV plugins are left out"

CinGG-qt6 compiles without any problems, but the OpenCV plugins are missing.
If I install OpenCV 4 from AUR, the build fails (build01.log with OpenCV 5 on the system; build02.log without OpenCV 5 on the system). At the start of the build, however, OpenCV 4 is recognized:

"ok opencv4 4.14.0"

But an error occurs during compilation. I think Arch, being a rolling-release distribution, has trouble working with OpenCV 4. I don't think it's worth updating CinGG-qt6 to work with OpenCV 5 as well, because it's incompatible with OpenCV 4 due to major changes between versions.

Speaking of the new plugins and their configuration, they work fine for me. Often, the Inspector window is too small for the number of configuration options, so you have to scroll with the mouse. It’s a bit inconvenient to see only part of the histogram, or the three Color 3-Way color wheels stacked vertically one above the other. In these cases, I prefer to make the Inspector a floating window and resize it to my liking.

Thanks as always, Sam.