Controlling the central heating boiler from your phone - request for evaluation of an idea

I have an eco-pea boiler with a feeder, it is controlled by a Rapid 3Z controller. I would like to be able to switch it on and off and view parameters remotely. I came up with an idea to solder a small 3.3V relay under the "start" button (directly to the microstick in the controller) and control the relay with esp. In addition, in order to get readings from the controller, I would solder to the LEDs and all the leads of the segmented LED displays and by measuring the voltages at these points I would know if a particular LED was lit or not, so I could know the status of the LEDs and even what was displayed on the LED display. Under the 230V outputs from the controller for the pump, feeder and fan I would connect relays with a 230V coil so I could also read on the esp whether these devices are working or not.
Has anyone tried controlling devices this way that have no external control?

Lots of issues , despite appearances, to solve . Switching on -off with relay contacts is possible, but do you need remote control? It is one thing to control a device, it is quite another to be able to control a device remotely. It is important to remember that no voltages must be introduced into the device from outside. Considering, for example, the blower motor control gives low and high speed so it's not a normal 230v. But you can draw a diagram and the comments will be more precise.

Actually on/off is the most important thing, it's just about simulating pressing one button (below is a picture of what it looks like) and that's how I thought that in order to have the least interference I wanted to connect a relay there under this contact. All the rest, i.e. reading of the LEDs, what the LED display is showing and the status of the 230V devices is to be without any interference, only checking the status, among other things, so you will know if pressing the start/stop button was triggered correctly.
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