Since you are trying to narrow down the cause it would be a good test to try @WTFDproject suggestion. Remove the sd card and see if the video feed improves.
We have seen a variety of problems on this forum that were caused by the sd card.
Filmed a hospital yesterday.. Glad I'm able to start off being able to see video to get camera angle then get message can't connect to camera after a few feet...When I bring it back I can re connect and stop record..The camera recorded all footage and looked perfect
@Davidg8862 perhaps you don't understand the objective. WTFDproject is trying to help you diagnose the problem and you are ignoring his request. He want's you to do a test flight without the sd card in the camera.
I should point out that @WTFDproject is the leading authority in the World on Yuneec cameras. He will not be able to help you find the problem until you begin to work with him. Do what he asks and answer his questions. Otherwise there is no point in pursuing this dialog.
I also have the same problem with my Q500, ST10 and CGO3 combo. I have great connections until the drone goes up a bit in the air, and then my video freezes / drops. I gave up, and haven't flown mine for a long time due to this frustration. Tonight I'm revisiting this issue and have been trying to find the a video of a fix I ran across several months ago (might have been over a year ago by now). The video I saw had a guy on it that indicated that the issue you are experiencing with video drop out is caused by a loose ground wire in the wifi (5.8) antenna. The guy I saw on the video appeared to know his stuff, but I haven't tested this fix. He also said the issue you (and I) are having is a very common problem with the CGO3. I will mostly likely take apart my CGO3 and take a look this week to see if I fix the ground wire issue where it connects to the antenna. I would love for this bird / camera to be working properly again. If it works or doesn't I'll report back. If someone else tries the fix, please let me know your results.