I ran a few rendering tests using a patched version of CinGG and AppImage (unpatched). I used two presets: h265-med.mp4 e H265-12bit.mp4. The presets used do not show any issues with the patched CinGG. There is a significant drop in fps; for the h265-med.mp4 preset, it drops from 105 fps to 16 fps. For the h265-12bit.mp4 preset, it drops from 71 fps to 14 fps. The rendered video displays the correct colors that the patches already showed in the Compositor. These presets (and the rendering file) include the “colorspace,” “trc,” and “primaries” parameters. However, I believe they only affect the metadata. Is there a way to tell if the color space of the final file has actually changed, beyond the metadata reported by ffprobe, MediaInfo, etc.?
So far, I’ve only run tests in X11; I’ll try Wayland as well.
One thing to understand is how patches affect the temporary directory and, consequently, how they affect rendering (if they do).

NOTE: mpv no longer works for me in X11 (with gpu-next) but it works in Wayland. I’m afraid that X11 apps will face more and more issues in the future.