How to get pixel position in non-geographical Leaflet map?

I have a problem, getting pixel coordinates in Leaflet. Any help would be greatly appreciated!

What I want to achieve:

I want to display an image using leaflet (no tiles – just a image, non-geographical map) and the user should have the option to click on the image, set a marker and I need the pixel position of that marker. For testing purposes, I’ve created a JSFiddle, that uses this image.

Displaying the image and setting the marker is not a problem. There are plenty of tutorials out there for that.

But getting that pixel position is – at least for me – somehow impossible. I’ve read every post / article / … about the different methods provided by Leaflet, but still no success.

What I achieved so far:

In an image editing program I can see, that the top of this tower on the image has roughly these pixel coordinates: x=1350, y=625.

Image showing the pixel position of the top of the tower

So when the user clicks on the top of the tower, I get the LatLng of this point and I can set the marker. When the user does not change the zoom level, my code is actually working. Clicking on the top of the tower, I get pixel coordinates, that are correct (see the blue marker on the image, showing where i clicked, and the pixels calculated displayed on the console):

Image showing the correct calculated position, if the user didn’t zoom

My problem

But when the user starts zooming, the calculated pixel coordinates are definitely wrong:

Image showing the wrong calculated position, after the user zoomed

My code

I’ve created this JSFiddle to share my code: https://jsfiddle.net/q36f1ytu/73/

The code that handles the click event is basically this (see my JSFiddle for the whole code):

map.on("click", function (e) {
  const marker = new L.Marker(e.latlng).addTo(map)

    // Here I want to get the pixel coordinate of the image
  var imagePixelCoords = map.project(e.latlng, map.getZoom())
  console.log("imagePixelCoords: " + imagePixelCoords)
})

I am quite lost, how to calculate the pixel coordinates correctly, when the user zooms.

Thank you very much in advance!

Best regards