we have a set up with almost 100 devices, it used to work fine some months ago when we had fewer, but now our main router constantly crashes because it just can't handle so much.
We had 8 routers set as access points and one main router as DHCP server, this set up doesn't work anymore, as such we decided to set another router as DHPC server in an specific section of the building, connected through the WAN port to the first router, and everything is working far better than ever.
Now, to do this we kept the main router network as 192.168.0.1 and we set the second one as 192.168.1.1, however, with this configuration devices can't interact with each other if they are in different networks. We need all devices to be able to interact with each other regardless of which network they are in.
We plan on setting more routers as DHCP servers for each section of our business as it really seems to improve stability and speed.