I doubt any other app would work for a device like that. Have you already tried contacting their support? If they don't have a contact email address in the manual, then it looks like you're stuck with trying to contact them through Facebook: https://www.camerafi.com/category/camerafi-live-manual/
Most of them are safe, but many don't work with "the generic endoscope". I found that Depstech-View Endoscope App worked for mine, and my endoscope isn't one of theirs.