Getting a NODEMCU to trigger the capacitive button on another device (Help!)

So this should be simple. I have a tea maker. It's not Alexa enabled. Fine I thought. I'll grab a NodeMCU, use the Sinric service and hey presto I can simulate a touch event.

Found some nice videos of people using the same setup to trigger the calculator on/off on an iPhone.

So I rigged it up.

D0 pin on the nodemcu goes to a short wire with a crocodile clip. Thats connected to a 9mm square battery connector so it has a good contact area.

the code is as follows

void setup() {

void loop() {
  pinMode(D0, INPUT);
  pinMode(D0, OUTPUT);

When I load the sketch and hold the metal against a button on the iPhone calculator the button lights up. So I know ground is working and triggering the capacitive screen. But it never changes. What I need is for the capacitive switch to go on and off. In the present configuration it seems the switch is always on. What am I doing wrong. I can seem to figure it

Im wondering how this is working in the following video

trigger capacitive touch from arduino to phone screen

You never get to see the full board. The code is posted on another site.