Making Simple GUIs, I'm surprised how hard this is!

I'm doing machine learning and I have a whole bunch of images I have to label. I didn't necessarily think this would be easy in a jupyter notebook, but I never guessed it would be this kludgy.

I want to display an image, capture xy mouse clicks, write some data to a file following a button click, then load the next image and repeat. I want this to run on windows, linux, and osx.

I'd prefer to not build a special conda environment for this. I'd prefer not to have to care about what back ends are available.

Is there a write once, run anywhere way to do this or do I need to write it in java or javascript?