It may also be your own phone that interferes with the WiFi, try to put the phone in flight mode. Additionally, it would be an advantage to let the controller / Anafi manage to find the shared channel to work on. The WiFi signal spectrum looks quite different from where Anafi is located than on the place you are standing. Locking up to a single channel is, in my opinion, the same as asking for big problems with the connection.
Fly safe, greetings Leif.
