The practical signal
If only the app is slowing down on the way, the camera is not the automatic problem. If each channel lags locally, the recorder or network load may be more relevant.
advice
Slowly investigate camera footage step by step
Delay must be compared per viewing route, because the same camera can react differently locally than via mobile internet.
The control sequence
Test one channel on the monitor, internal Wi-Fi, and mobile internet with the same moving reference point. Note whether the delay is constant or mainly occurs under heavy image load.
What is smart to do
Adjust the found route: stream profile, network, viewing device, or specific channel. Do not make a broad quality reduction if the comparison does not show a bandwidth problem.
When it is completed
Repeat all three tests after one change and check that recording quality has not unintentionally deteriorated. Document the chosen balance.
Frequently asked questions
Why is the app slower than the monitor?
The app uses a different network route and often a different stream.
Can an old phone cause delay?
Yes. The viewing device is a part of the total route.