Siding, stucco, and brick are some of the toughest exterior walls for signal to travel through. While the Chime Pro should help improve your signal strength, this may not be fully accessible due to the siding. I recommend avoiding any further interferences on the inside of that side exterior wall. Any mirrors, appliances, or large furniture will only dampen the signal further. Also, If possible, try mounting the Cam in a different location where the signal is stronger. Hope this helps!
I recommend that you go with a mesh Wifi system such as Google WiFi. It's $250 for 3 nodes, but they will pretty much cover a normal sized home with great wifi. I added a fourth node to my Google WiFi, and mounted a Ring camera on a light pole 150 feet away and through a brick wall. It has good signal strength (RSSI -58), and I haven't had any issues.
A side benefit of the Google wifi (and I assume other mesh networks) is that your other devices will have great connections to the internet anywhere in your house.
I have 2 doorbell3 and chimes. In one house (wood) the battery lasts for weeks with motion detetion turnerd off. On the stucco house with metal door set same way battery doesn't last a week (usually 4 days). Unless there is something wrong with the doorbell I assume that it is due to the stucco (wire mesh) walls and metal door. Wifi strength is low in that site.