I've got a mixed home network with three M4s and two W2400's. I'm trying to extend my wifi to the furthest part of my house which is beyond "Jim's Bedroom" in this network diagram which is taken from the web app.

However, Jim's bedroom is actually quite distant from the main node "Office" and closer to the "Kate's Room" node as shown here.

Every time I try to tune the network or otherwise turn things off and on again to try to force Jim's node to connect to Kate's node and not the Office, it doggedly connects to Office with a "weak" signal. When I first set up the network, it was set up what I perceived to be correctly, Jim's node connected to Kate's. Nothing has moved it's just no longer doing that. Any suggestions? Here's the list of hardware and everything has the most recent firmware. Would it be helpful if I made sure that the Jim and Kate nodes were the same model units? Anything else I can try? Thank you for suggestions.