homeassistant

It depends, but I'd say you should definitely try it. Zigbee is so cheap (not just initial cost, but batteries also last waaasy longer and it doesn't saturate your local network), and it's very possible you can still build a nice mesh, maybe reusing a couple of your Wi-Fi switches somewhere else in the house if you need a Zigbee router in one of those spots.

It was never the best idea to fill your home with tiny Wi-Fi devices. Wi-Fi IoT devices are more for people who basically want to automate a couple of things, not 40. I would become mad just for the battery changes, and scared as heck I'd be toasting my brain with so many devices screaming radiowaves (and a clear slowdown of my Internet connection).