Re: "The Fujifilm XF 23mm f2 R WR is..." - while that is a solid lens, you can actually save quite a bit of money by looking at third-party options that perform just as well for street work. If the budget is a hard 500 dollars, these are decent alternatives:

• TTArtisan 27mm f2.8 AF Fujifilm X Mount is a great budget pancake. It is significantly cheaper than the Fuji version, leaving you cash for travel. The AF is decent enough for walking around NYC, tho it can hunt a tiny bit in low light.
• Viltrox AF 23mm f1.4 XF gives you a much wider aperture than the Fuji f2 for less money. Its great for night street photography where you need that extra light.
• Sigma 30mm f1.4 DC DN Contemporary for Fujifilm X is incredibly sharp. It is a bit larger than a pancake, but the image quality is top tier for the price point. Basically, these third-party lenses let you hit your goals without blowing the whole budget.

The Fujifilm XF 23mm f2 R WR is the technically superior choice for the X-S20 system! Since your camera has that incredible autofocus tracking, you really want a lens that can keep up with the sensors speed. The 23mm uses a stepping motor that is basically instantaneous and silent, which is fantastic for candid shots. Here is the technical breakdown why I love it:

• Focus speed: The 23mm f2 is significantly faster than the 27mm pancake lens.
• Weather Resistance: The R WR version handles NYC grime and light rain perfectly.
• Low light: That f2 aperture gives you an extra stop of light over the pancake, which is amazing for night street photography. The Fujifilm XF 27mm f2.8 R WR is definitely tiny, but the motor is an older design that moves the entire lens assembly. It feels a bit clunky. If you want pro-level performance for under 500 dollars, the 23mm is the way to go for sure!

Building on the earlier suggestion, I have spent over a decade shooting in busy cities and I have learned the hard way that gear reliability is way more important than having the smallest setup possible. I remember being in Chicago years ago with a lens that had a slow motor and I missed a shot of a lifetime because the autofocus decided to hunt for just one second too long. It is a terrible feeling when you are on a trip you have looked forward to for months. In my experience, you want a lens that you can trust implicitly when things are moving fast. NYC is chaotic and you do not want to be fighting your gear.

• Distance: I actually think the Fujifilm XF 35mm f2 R WR is a safer bet for a beginner. It gives you a bit more distance from your subjects so you dont feel like you are sticking a camera right in a strangers face. It keeps you more low key.
• Internal focusing: This is huge for safety and reliability. Both the 35mm and the Fujifilm XF 16mm f2.8 R WR focus internally. Nothing moves on the outside, so there is less chance of bumping the barrel or getting grit in the mechanism while you are in the subway.
• Motor speed: The 27mm pancake is cute, but that motor is older tech and definitely loud. In Manhattan, everything moves at light speed. You want the snappier motors found in the newer f2 primes. I would personally grab the 35mm. It fits your budget and it is a total workhorse that wont let you down when the light gets tricky or a subject is walking fast toward you.

• Ive been agonizing over this same choice because that price difference is huge!
• Its honestly the most frustrating decision ever. Quickly tho, are you shooting mostly day or night?