I have considered going to OBS as well, but I prefer the simplicity of QuickTime and I have no real need for the additional features of OBS.
I have been through at least two phone sessions with a friendly Apple tech, and I was instructed to send debug data back to Apple. They have yet to call me back, so after Christmas, I will contact support again with the active case number. I was hoping the most recent Monterey update would have fixed it, but recordings still end at 10:55. Photo Booth also won't work for recording video as it doesn't record sound off my USB capture device, and the video is reversed (though that can be easily fixed with FCP)
Another Apple tech in a support chat also suggest reinstalling macOS. I feel that is rather extreme as besides QuickTime, I've been having no issues with Monterey, and I would have to spend an hour or two setting up all of my preferred apps to what they were before.