Edit: heck I bet most consumer grade routers DHCP servers would choke after the first 255 clients (probably much sooner) just from having to change subnets. I’m not a networkologist though so IDK for sure

As somewhat of a networkologist I can say that most home routers use the 192.168.something.x IP range. With a subnet mask of 255.255.255.0, this means that you could put 253 clients on the network (2 of the IPs aren’t usable for devices). After that, you would have to change your subnet mask to something larger, which is easily doable in router config. However, a home router likely wouldn’t work well with even just 100 devices connected. WiFi is also half duplex, meaning it can only send or receive, but not both at the same time. This would make the speed unbearably slow. You would really need multiple radios/access points to have this many devices.