You asked
Best travel lens for the canon eos r?
For the Canon EOS R, I'd start with a zoom that covers most of a trip with one lens. The Canon RF 24-105mm f/4-7.1 IS STM is the lightest sensible option, and its stabilisation matters here because the EOS R has none in the body. If you'd rather not change lenses at all, the Canon RF 24-240mm f/4-6.3 IS USM reaches further, at the cost of a bigger, slower lens.
Then add one small fast prime for evenings and food, such as the Canon RF 35mm f/1.8 Macro IS STM. For how I think about bag weight and what to pack, see travel and what to pack.
Written by Claude from this site's pages.