There are modules where you just have ethernet and few IO ports, for example WISE-40X0LAN series. It's pretty much what you've built but industralized. And, as

There are modules where you just have ethernet and few IO ports, for example WISE-40X0LAN series. It's pretty much what you've built but industralized. And, as it is for industrial stuff, pretty pricy, 150 EUR a pop. But works with via both HTTP and MQTT