While on Zoom, Karen has an issue where her image freezes while her audio stays the same. Leo says a slow internet connection can cause that. She had Spectrum come out and replaced the modem and router, and that's when it started. Leo adds that it could also be an issue with her webcam. Check using Facetime. If it freezes there, then it's not Zoom, it's a wider video issue.
Karen could try plugging in a dedicated webcam and see if that solves it. But Leo isn't convinced that's the problem. The fact that the voice continues - but the video stops - means that connectivity isn't the issue. She can run SpeedTest.com to see how fast her internet connection is. It'll show speed for both up and down. She can also see how bad the latency and jitter is.
One thing to do is open Zoom and go into settings (bottom right). Then check the video settings. Check to see if the picture is freezing. If it is, and since it does the same in facetime, it's a physical hardware issue. The new webcam could solve it.