Glitching? Well yes, me too. And by glitching I mean Zoom does not see ManyCam Virtual Camera at all. Just the built in Facetime Camera, that's it. Tried uninstalling, reinstalling, upgrading both ManyCam, Zoom, MacOS; even uninstalling and installing ManyCam 7 instead of 8. Nothing. Found some creepy Apple article that I tried doing in 'Terminal' but I run from a remote boot through Thunderbolt off of an SSD so 'starting in recovery mode' and editing in Terminal is weird on a remote external partition build. But funny enough, my old 2012 MBP works fine. Something is fishy between ManyCam, Zoom and MacOS Sequoia 15.0.1. Old machine is great; all this expensive new stuff is an incubator lab, where my work, reputation and income go to die. So yes, "glitchy"

https://support.apple.com/en-us/108387

If you can't use your camera or video output device after updating to macOS Sonoma 14.1

It is not clear why you are using ManyCam. However, you might want to look at OBS Studio instead, which is free and far more versatile. It supports NDI input and output and has numerous plugins to add features. There are thousands of youtube videos explaining how to use it.