So I have been using various relays over 2 last years, mostly driven by Tinkerforge I/O modules but they sometimes prone to interference from the 230AC and sometimes do freeze or I/O module is registering bogus inputs. Especially when used next to the large loads like 2kW poll pump.
So I look for some other module that would have relays or better relays and some inputs for registering button presses.
Needs to be super reliable. With wired Ethernet and POE
The ITead/Sonoff, while popular because they’re the cheapest (plus because there’s an alternative firmware available), clearly they’re NOT the most reliable ones which is what the OP is looking for. They’re even known for some incidents they caught fire.
My advice would be to put another relay in line, to minimize electrical feedback.
I definitely do not look for the cheap option as with switching a load that is close to the max relay capacity is very stressing on the hardware.
I had a case that 2kw boiler heater was operated with cheap SONGLE relay got stuck in on position and my IR Camera showed it @ 125 deg C , So it was hours away from starting fire. I moved that to the 25A Solid State relay and never had a problem again
Back on topic, My main interference problem is coming from the PS of the relay board not from the load itself. I tried adding large mechanical relays that disconnect both phase and neural and that did not help. I still need to power the relay board, and if it has some inputs those get interference as well.