I’m afraid the answer to your question is… “It depends”.
Factors which affect range include the structure of your house - what walls are made of, how big rooms are (bigger is better) - and what router devices you have - some have a stronger signal than others (generally plugs and sockets are better than bulbs).
In the right setting a Zigbee signal can reach quite a long way, but I believe the recommendation for a stable network is a router every 10-15 feet.
Bear in mind that messages don’t just need “a path” from A to B, they need many different paths. Routers change their connections all the time depending on traffic. Looking at your map, you only seem to have five routers and there don’t seem to be many paths between them. Mine looks like this:
(The paths shown in the map are not necessarily the ones being used - the represent every possible path Zigbee has discovered.)
A good approach is to build a network of routers with lots of connections between them, and then add the end devices. Be careful what devices you buy - there are a lot of cheap buggy ones out there which will cause problems however strong the network is.
You’e probably read up on the community guides already:
