ZHA controls a mesh network, so the range of an individual device is totally irrelevant. What is important is that there are enough mains-powered routing devices to give more than one path between nodes - a mesh.
So, no, I’d suggest not switching from one of the best Silicon Labs chipsets (albeit with a small antenna and an unpopulated J9 IPEX / U.Fl connector bottom left) and instead buy more devices. Cheap IKEA TRÅDFRI mains switch sockets work well.
I’d instead read…
If this helps, 
this post!