Moving on to the ultra wides, the phones' approaches diverge, which becomes readily apparent in the coverage. The Galaxy and the iPhone have the widest field of view, and it's as good as identical between the two even though the iPhone EXIF info reports 14mm and the Galaxy's says 13mm. The Xperia is a little tighter but still very wide at 16mm. Meanwhile, the Mate's 18mm equivalent means it offers the narrowest field of view, plus its camera is in a different aspect (3:2 vs. 4:3 on the others), so it will further limit what you can capture vertically.
What the Mate 40 Pro lacks in coverage, however, it easily makes up for fine detail. None of these other three can hold a candle to its resolving power, a combination of the highest-res sensor and its high-quality optics.
Between the Galaxy, the iPhone, and the Xperia, it's really a toss-up for detail, though perhaps the Note's ultra-wide does lose by a narrow margin when it comes to edge definition if you insist on looking carefully and for long. On the flip side, it's about this much superior in noise reduction - hardly any noise in its photos, minor speckling in the iPhone and Xperia shots.
The iPhone and the Galaxy maintain their parity beyond coverage too. Color reproduction and dynamic range are so similar most of the time that we'd be hard-pressed to tell them apart in a blind test. The Xperia is easier to spot - it tends to expose darker and has a more limited dynamic range.