RF 24-70mm f/2.8L IS USM. https://www.bhphotovideo.com/c/search?Ntt=Canon+USA+3680C002+24+70mm+F2+8&BI=8941&KBID=10361&SID=12345&DFF=d50

TL;DR: Everyone says 24-105mm or 24-70mm, but I found the Canon RF 24-105mm f4 L IS USM pretty disappointing because of the distortion. For real versatility, the Canon RF 24-240mm f4-6.3 IS USM is a better all-in-one even if it isnt a pro lens. To add to the point above: I really wanted to love those L-series zooms everyone mentions, but honestly, my experience was a bit of a letdown. I took the 24-105 out for some mountain shots and the vignetting was just brutal at the wide end. I ended up spending way too much time in post... it felt like I was fighting the gear the whole time. I even tried some DIY calibration stuff at home to see if it was just my copy, but it just seems to be the way they are built nowadays. Basically, the thread is split between the f/2.8 speed and the f/4 reach. If you want a lens that actually covers everything without swapping constantly, look at the Canon RF 24-240mm f4-6.3 IS USM. It isnt as sharp at the corners, sure, but it is way more versatile for travel than the pro glass that always leaves me wishing I had more zoom... kinda makes you wonder if the L badge is worth the extra weight sometimes.

The most versatile lens for Canon RF cameras is widely considered to be the Canon RF 24-105mm F4 L IS USM. This lens strikes a balance between a broad focal range and consistent image quality, making it suitable for various photography styles, from landscapes to portraits.

I’d argue the RF 24-70mm f/2.8L IS USM is the most versatile. The f/2.8 aperture gives you better low-light performance and more background blur, and the focal range is perfect for everything from street photography to events. It’s a bit heavier and pricier, but worth it if you need that extra speed.

Based on your budget.

RF 70-200mm f/2.8L IS USM Z lens. https://www.bhphotovideo.com/c/search?Ntt=rf+70-200mm+f2.8+canon+z&BI=8941&KBID=10361&SID=12345&DFF=d50