Hello @robertklep,
thank you for your insight:
robertklep
Homey has a hardware limit of about 20 directly connected devices. Sadly, you can’t force devices to connect through a router instead of with Homey directly, so the only way to fix your mesh is to remove a number of end devices (battery powered) from Homey, replace them with additional routers, and add the end devices back again from the location you intent to use them (so not close to Homey). That way, you have a bigger chance of the device connecting through a router (in my experience some devices, mostly Xiaomi Aqara, seems to have a preference to “stick” with the router that they got initially paired with, even if that router isn’t the most obvious choice w.r.t. distance).
Thanks also to @Gilly_Wings, @Satoer and @MarcoGr.
I have found a way how to connect new Aqara devices via another router device (even in close proximity to Homey). Robert’s comment gave me the idea that worked. I have used an aluminium foil as a shield between the newly added device and Homey while the new added device being close and unshielded to the router device.
Well, it looks a bit weird when arranging the “dumb” foil in order to add a “smart” device, but it works 
.
So thanks again and I hope this helps others in return.
Cheers,
Martin
