No snark intended here: what exactly don't you like about the RF-S 10-18?
And the 18-45?
The RF-S 10-18mm has good IQ and the f-numbers are fine for a UWA lens unless you´d like to take night shots or photograph in low light. I don´t like the build quality though. The plastic feels really cheap and not durable. Furthermore, the two copies I tested, it was hard/ very fiddly to use the control ring. Plus, since it is very small, I'd often turn the control ring while I was zooming. Those were my main issue with the horrible ergonomics on this lens.
For the 18-45mm, I found the ergonomics to be troublesome as well. Furthermore, Canon had a EF-S version with better F-numbers and a EF-M version that is 3mm wider, but Canon somehow decided to ditch those two and come up with a lens which is "worse" in comparison to either one. I know, these two lenses are all about "size", but I as pointed out, the small size does become an issue (for some) and I don´t feel like the advantage justifies the loss of aperture or focal length at the wide end, particularly because the other two lenses weren't extremely large in comparison.
I´m absolutely not opposed to f7.1 or f8, but it really has to make sense. With the RF 100-500mm and RF100-400mm I´ll gladly take f7.1 and f8 for a smaller lens or more reach, but f6.3 to top out a zoom lens at 45mm? Honestly, no, it really doesn't make sense to me and it nothing I´d ever appreciate. Going from F4.5 to F6.3 in the 18-45mm zoom range is just bad. While with the UWA it is ok imo because one mainly uses it for landscapes. The 18-45mm focal length is typically one where hobbyists also take pictures of family and friends while traveling and F6.3 just doesn't appeal to me for taking pics of people.
I know, the lenses will appeal to a lot of people, they just don't do it for me. Maybe, my hands are too big or my motor skills are not developed enough to handle those lenses properly

but I think that some people here do agree.
If Canon comes up with in my opinion "reasonable" lenses for APS-C, I´d gladly purchase a R50/ R10 or whatever camera they are coming up with this year. Until then, it is a "no thank you". I´ll be looking elsewhere for a lighter camera (as of now, I´m still eyeing the R8... but no joystick for over 1 k €...grrh)