Ngl I spent way too much on the Canon RF 24-70mm f2.8L IS USM and it really wasnt as good as expected for a long trip. Carrying that brick was a huge mistake and I had issues with the weight constantly... unfortunately my neck was killing me by day three. If you're on a tight budget and worried about buying used, just grab the Canon RF 24-105mm f4L IS USM and save your cash for the actual vacation. Tossing a cheap Canon RF 50mm f1.8 STM in your bag is a much better move for those night shots of the kids. It weighs basically nothing and keeps you way under that $1,800 limit. Honestly, having that extra reach to 105mm is way more useful for random street shots than f/2.8 is anyway. The R6 stabilization is so good you wont even notice the slower glass.

Jumping in here... I went through this exact struggle before my last trip to Kyoto. I ended up grabbing a used Canon RF 24-70mm f/2.8L IS USM and honestly, be careful. I noticed some soft focus on the edges that the seller didnt mention, and since I had no warranty, I was just stuck with it. Japan involves so much walking—like 20k steps a day—and that 2.8 gets heavy real fast. I would suggest this setup instead:

• Get the Canon RF 24-105mm f/4L IS USM brand new so you have a solid warranty for the trip.
• Spend the leftover cash on a Canon RF 35mm f/1.8 IS Macro STM for those night shots of the kids.
• Use the 105mm reach for those distant temple details you cant get close to. The f/4 is plenty for daytime and the R6 sensor is a beast anyway, so you wont miss the f/2.8 as much as you think. Tbh having a small prime in your pocket for dinner is way better than lugging that huge 2.8 brick all night.

I would suggest the Canon RF 24-105mm f/4L IS USM for travel. Be careful buying a used Canon RF 24-70mm f/2.8L IS USM.

• more range
• lighter weight The R6 sensor handles low light perfectly.

My buddy told me the exact same thing last week. Guess he was right lol.

This ^

Late to the party but this whole Japan talk makes me think of my last trip there. My camera strap bracket actually sheared right off while I was hiking up near Arashiyama. I didnt have any backup gear so I had to use some paracord and a keychain ring to rig up a makeshift carry system on the fly. It looked pretty janky but honestly I was so satisfied with that DIY fix. It worked well enough that I didnt even bother looking for a real replacement for the rest of the month. I ended up finding this tiny hardware shop in a back alley that sold this incredible industrial adhesive to secure the knots. Spent way too much time just browsing their tool section instead of actually shooting photos... such a cool experience tho. Makes me want to go back just for the snacks.

To add to the point above: everyone seems to agree that the 24-105 is the safer bet for travel, but unfortunately the technical performance of that lens is just not as good as expected for the price. I have had issues with the chromatic aberration at the wide end, and the MTF charts really show how much it struggles compared to the primes. If you are a pixel peeper like me, you'll probably be disappointed by the corner softness even at f/8. Funny enough, that reminds me of my last trip to Osaka where I spent half my time trying to find a specific type of high-speed SD card because I forgot mine at the hotel. I ended up in this massive electronics department store that had like eight floors of gadgets. I got so distracted by the floor dedicated to vintage model trains that I completely forgot why I was there in the first place. Spent way too much money on a tiny replica of a Shinkansen engine instead of gear. Anyway lol.