I have had my doorbell for a little over a month now. I’ve watched the RSSI readings a lot (fortunately I am retired). Sometimes they are good, other times not so much. I had tried sticking a second router between my primary router and the db to act as a redirector. Without that secondary router the db simply did not work (RSSI about -83). With that secondary router it was better (RSSI around -70, but too often worse).
I purchased (Amazon) a Netgear EX2700 extender (about $25). It extends the primary router’s signal but has a different SSID and therefore only the db is on that ‘network’. Currently I am getting a rather stable RSSI of -59. That leaves a little room for network flakiness etc. At the moment I have the extender plugged into a power strip plugged into an extension cord to get the best placement of the extender.
I have no financial interests in Netgear.