When a user uploads an image using the ACF Image field, and a maximum height and width is set, is there a way in which an image menu could appear (like the one WordPress already has in the media library)? So that the user can crop the image?
There's a plugin with an additional field typ with which you can force the user to crop the image to a specific size: https://github.com/andersthorborg/ACF-Image-Crop
It's not clear if it's still under active development so you'd have to test it with newer ACF versions.
There's also one with aspect ratios instead of sizes if you need that: https://wordpress.org/plugins/acf-image-aspect-ratio-crop/