This is exactly how I am setting my house up as I slowly gut and rebuild every room.
The only difference is that instead of running all lines back to a central location for the house, I run all lines back to a central box for that room.
In that box is an I/O board that communicates via MQTT over wired Ethernet (some with PoE) to Home Assistant. Switches, buttons and other low voltage inputs send control signals, then outputs trigger stuff (mainly relays). The boards also have sensors (DHT22, BME280, RFID, etc. etc.) depending on what else is needed.
No critical / permanent infrastructure on WiFi. Though WiFi used for things like power bars because they move around sometimes. Or for temp stuff.
Now you’re going to ask me where I bought these boards. I didn’t. I couldn’t find anything that met all my requirements (a big one of those that I control the firmware) so I had to design them.
If you don’t want to go through the whole fabrication thing, then there are Arduinos with built in Ethernet where all you have to do is add the I/O. Superhouse makes high quality, reliable products for this. Yes, you’ll pay more than WiFi. Yes, it will still be running 100 years from now. 
They don’t have any opto-isolated input shields, but Google found a bunch.