Maybe you know 'Brian\'s index Nozzle calibration tool' or TAMV or kTAMV (k for klipper) ? These tools use an USB (microscope) camera, often with build in leds for the exposure of the object. The tools make it easyier to determine the XY offsets for the Z-probe or for a multi toolhead setup.
My 3D printer has 2 toolheads, a 3dTouch Z-Probe and runs Klipper.
kTAMV, for Klipper, failed sometimes to detect the nozzle on my printer or the offsets were just off. Sometimes its caused by a not clean nozzle but a new, clean, dark colored nozzle also failed. Its not always clear why it went wrong. Its not possible to manually select a detection method or to tweak the parameters of the used methods. The detection methods are global and not per extruder.

This app, minimum Android 8.0+ (Oreo), uses OPENCV's blob, edge or hough circles for nozzle detection. Select None (no nozzle detection) or one of the 6 nozzle detection methods. Per extruder the selection and preparation method can be selected manually. But an automatic find "Find 1st fit" is also possible. This performs a 'brick' find, through the preparation and then detection methods, until the 1st solution with only 1 blob detection. When the found solution is confirmed during a number of frames the find stops. With "Find continue" the blob detection is forced to continue with the next method or preparation method. It now includes a kind of microscope-camera-moved-detection.

Almost all parameters can be tweaked, most of them per extruder. There is ample opportunity to screw image preparation and/or nozzle detection up.

If you don't have an Android phone you can run the app from your home computer using an Android app player like Blue Stacks, LDPlayer, or other alternatives.

Note: The app could be a heavy CPU load and memory consumer for your phone. The app will drop camera frames depending on the speed of the phone. Within Klipper the webcam frame rate can be set, probably for internal usage in Klipper, but via the network the app still gets the full frame rate (in my case ~14 fps) of the camera.
I use microscope cameras with USB cable (check its height before buying, the USB cable adds 4-6 cm).

Before you start:
- set all gcode offsets to zero in the Klipper configuration file
- clean all nozzles of any filament particles
- retract the filament, per toolhead, 2 mm so that the filament is not visible as a blob in/on the nozzle
- make sure the microscope camera has a solid pedestal and does not move due to vibrations when the toolhead/bed moves (via the USB cable !!).
I had to 3d print a pedestal, added thin rubber pads to its bottom and pin down the USB cable to the bed before it was stable.
- home all axes before you position the camera on the build plate.
You will have to 'lower' the buildplate before the camera will fit.
Manually adjust the focus of the camera.
Pin the USB cable to the build-plate to prevent very tiny movements !!!
- Select a reference extruder from which the other extruder offsets will be calculated.
If applicable, start with the extruder which has the Z-probe attached too it.
- Note: 'dark' nozzles are much more difficult to detect