Main network works fine, but i have to unplug one of my 3 points for anybody to connect to Guest Wifi.
If I plug it back in, i'm thrown off and on 4G.. at least if in vicinity (which is hard to avoid when connecting to power)
It's the mid point and probably the one with most coverage in house.
Maybe you got too many points too close?
Could also be worth to try a factory reset of the problematic point and re-add it to the Google Home home network. Eventually factory reset the whole netwoek/ ll points and set up from scratch.