Like someone mentioned, you are weighing the 23mm and 27mm. I have tested both over the years and honestly, the Fujifilm XF 35mm f2 R WR is the sharpest f2 prime for that 40MP sensor. Its fast, tiny, and way under your 600 buck limit. Quick tips for the trip:

• Set shutter to 1/500 minimum to stop blur
• Use AF-C with Zone focusing Basically gets you better results without breaking the bank.

Unfortunately, my 23mm wasnt as good as expected for sharpness... Are you shooting mostly candid stuff? The Fujifilm XF 27mm f2.8 R WR is only $400 and way stealthier for NYC.

Just get the Fujifilm Fujinon XF 23mm f2 R WR. Its crazy fast and the field of view is way better for street shots than the 35.

Quick thought while I have a sec... but I need to ask, what is your typical distance from the subject? If you are shooting from across the street versus being right in their face, it changes the focal length math entirely. Be careful with some of the older glass on that X-T5. That 40MP sensor is really demanding and will show every flaw if the optics are not up to par. I have seen too many people buy glass and wonder why their high-res files look soft.

• Honestly, just get any prime from Sigma. You can't go wrong with their glass quality for the price on Fujifilm bodies.
• I would suggest looking at the Viltrox lineup too if you want to save money for your NYC trip.
• Make sure to keep an eye on PriceDropCatch if you are hunting for a deal, prices on those third-party lenses can dip right when you need them. If you want the fastest AF tracking, native glass is usually safer, but those other brands are catching up fast.

Wow ok that changes things. Gonna have to rethink my approach now.