Hey there, @Mattdj. It is surprising to hear the Chime Pro did not improve signal strength. Most standard routers should be sufficient for providing signal and resources needed, however, a router provided by your internet service provider could certainly be an older or less advanced model. Try checking the router specs or manufacture date, or even inquiring with your internet provider to see if they offer better equipment.
Location is key for wifi signal. Before looking for a new router, I recommend adjusting the router and Chime Pro locations in respect to each other and the Video Doorbell. Optimal signal strength will be best found through trial and error. Feel free to check out our Community post about RSSI for tips on optimising signal. I hope this helps! 