If one WiFi network is loading, the other is not working, what could be the matter?

Question

WiFi

Hello,
The apartment has two WiFi routers that work with two different providers. Network addresses are different. If you start downloading a file or a torrent on network A via WiFi, there are problems with the speed of network B via WiFi. The channels in the settings are different (2 and 8).
What could be the problem and how can I try to solve the problem?
Thanks for answers.

Answer 1

Problems can only be in the channels. It is necessary to select channels that do not intersect with each other in any way, then there should be no problems.
It is worth noting that some channels partially overlap each other, so it is better to choose 1, 6, 11 or 2, 7 or 3.8 or 4, 9, etc.
See the diagram:
But it's better to choose 1 and 11, so you definitely won't lose.