Zigbee "button" I could connect an external source to

Short version.
I have a brass door bell. It’s designed to be hard wired, but at the moment a push presses down on a cheap wireless doorbell, which rings as it should. As a door bell it works fine.

What I would like to do is have this connected to a zigbee button or similar, and pressing the brass button triggers it. Soemthing like a xiaomi smart button that accepts an external connection. Does such a thing exist?

There’s no power at the button so it needs to run on a battery with quite long life. No issues with weather.

If not I have a spare xiaomi button, I’ll try and do the same thing with it (or pull it apart!) but though I would ask the collective mind first.

I’ve not used the button, but you can certainly achieve it with the door / window sensor.

It’s easy to open the sensor part, and solder wires to either end of the reed switch, make the contact and it reports closed. I use them to sense if my door is locked. The batteries last forever and they look quite neat.

Oh I absolutely forgot about that trick. Might be a good excuse to order one!