Focal length wouldn't even be an issue if the photographer was taking the photos from the same position. The fish-eye effect is literally because the photographer is closer. Cropping a photo with a different focal length will give the same composition and difference will be the distortion introduced by the camera and the image processing.

100% -- "zoom with your feet"

To your point, back up to where you'd shoot the long lens, then crop back. Thanks to the 48mp, there's room to crop, it'll be fine.

FWIW, this crop is what every* camera with a sensor smaller than full frame is already doing to get "reach" from smaller glass, whether we realize it or not.

* By and large.