Basically, i went through this exact dilemma when I first got my R10. I ended up picking up the Canon RF-S 18-150mm f3.5-6.3 IS STM for a backpacking trip and it was a lifesaver. Its super lightweight so it doesnt feel like a brick around your neck after 10 miles of walking. The range is decent enough that i could get wide shots of buildings and then zoom in on details without fumbling with gear in the rain. I also brought the Canon RF 28mm f2.8 STM just in case things got too dark at dinner. It's tiny, basically a pancake lens, so it fits in a jacket pocket easily. Tbh the 18-150mm stayed on 90 percent of the time tho since its just so practical for the price and covers basically every situation you run into while sightseeing. TL;DR: The 18-150mm is the best bang for your buck for an all-in-one travel setup.

Re: "Basically, i went through this exact dilemma when..." - i totally agree that the 18-150mm is a solid all-rounder, but honestly it depends on what your travel actually looks like. Last year i spent two weeks in Kyoto and i realized halfway through that my zoom was just too slow for the night markets and moody temples. Quick question for ya tho... are you planning on shooting a lot of indoor stuff or mostly outdoors during the day? Because that changes the technical side of what glass makes sense for the R10 sensor. If you want something faster or wider, here are a couple i usually toss in my bag:

• Canon RF 35mm f1.8 Macro IS STM
• Canon RF-S 10-18mm f4.5-6.3 IS STM I've found that having a fast prime like that 35mm makes the R10 feel like a totally different beast. It basically turns it into a street photography machine... much better for low light than the kit zoom. But yeah, let us know what you're actually aiming at and i can give better advice.