Here Google say to keep the network at 5 devices or below
https://support.google.com/googlenest/answer/7182840?hl=en-GB#:~:text=Maximum%20number%20of%20Wifi%20routers,devices%20in%20a%20single%20network.
No solution here but also an issue with my Garmin Fenix 6X Pro wtach. It
won't connect to the wifi because it is not 2.4Ghz and if I set up the
connection the battery dies in one day as opposed to expected 2 weeks,