Best Systems for Remote Control of Home Devices via Internet with Mobile App

Can you recommend any system that will enable me to switch on/off various devices in the house remotely (via the internet)? It is important that it has an interesting (nice and functional) application for the phone.

The ideal would be a module which I mount in the switchboard (on the TH bus) or next to the device, connect the LAN, set the icon in the application, click on, click off It would be good if the modules were available with one and several outputs. Affordable price also welcome .

How about Supla:
https://www.supla.org/pl/
You can use factory-made actuator modules or build one yourself, e.g. on ESP8266 based on Arduino.