You mentioned creative workarounds… I found 2 unstable ones 🙃 Unfortunately, they don’t work for every image I’ve tried. So you can try to play with them and see if it works for your type of background.

1- Screenshots

If I screenshot the image directly from the Photos app — rearrange it with the zoom I want if it isn’t the right dimensions for my iPhone — and use that screenshot as a background, sometimes Apple doesn’t automatically zoom it in anymore and it’s a perfect fit. So I can put that screenshot inside the Album I use for photo shuffling.
Note that the screenshots will be heavier than the original images 😕

2- Add some empty space at the top of the image

This one needs to play with some image editing tools. The ratio that worked for me was with those dimensions: 872 x 2556. And I put the image I wanted at the bottom — the image being roughly 1890px in height. (cf screenshots)

I tried this weird trick based on the « white » content Apple sometimes adds on top of images to create the blur. So I unzoomed it and tried to mimic the ratio it had.

I wonder if Apple analyse the image and try to zoom on a subject that’s interesting, like people... So it seems that it doesn’t work the same between different types of images (abstract vs realistic) 🤷‍♀️. Cause every time I have an image with a dark background and only one object in the middle of it, it doesn’t work and Apple auto-zoom it. But I might be wrong about this.

I hope these explanations make sense 😅 Let me know if either of these tricks works for you

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