Hey, First let's talk about their Rear camera specification, Galaxy Note 20 Ultra has a 108 MP main sensor that clicks 12 MP photos by default.
The second camera is a 12 MP ultra-wide camera, and a 12 MP telephoto camera.
Whereas, The iPhone 11 Pro Max has 12 MP sensors in its all three lenses.
On the front, A 10 MP selfie camera on the Note 20 Ultra and a 12 MP camera on the iPhone 11 Pro Max.
Results: both have done an excellent job, they both give a high dynamic range.
The difference I have noticed is iPhone photos are a bit warmer and Samsung photos are natural with colors
The Galaxy Note 20 Ultra’s camera has 5x optical zooming and can then go up all the way to 50x digitally-assisted zoom. The iPhone 11 Pro Max’s telephoto camera gets you a 2x zoom and can crop down to 10x digital zoom.
So if you want some extra features also in-camera then I will suggest you go for Samsung