David Pierini has a good look at third party camera lenses for iPhone 11 Pro:
If you are a pixel-peeping stickler for quality, the ultra-wide camera may disappoint. The ultra-wide camera does not support RAW shooting or Apple’s new Night Mode. It also has a slow aperture at f2.4, meaning the lenses will not allow in as much light as the iPhone’s standard camera.
Check out the side-by-side comparison photos of iPhone 11 Pro camera shots vs third party lenses.
The higher quality shot will come by placing one of these third-party ultra-wide lens attachments to the standard camera, which has a focal length of 28 mm. With it, you can shoot RAW, an uncompressed file that records more detail and greater dynamic range. You can also take advantage of Night Mode for low-light shooting.
Surprisingly, not very expensive. It will be interesting to see how those lenses work with Deepfusion.