I've been doing a lot of video landscape setups on the C70 (over 100, I think) and my absolute workhorse has been the RF 15-35mm f/2.8. That's a Super 35 sensor, so lens is equivalent to something like a 22-50.
The range of focal lengths has been superb for almost everything -- I have on occasion used a 50mm lens, but *very* rarely. The 15-35 almost never comes off the camera. I sometimes think I might want a longer lens, but 35 almost always turns out to be enough. Being able to go wide is great -- I go to 24mm quite a lot, sometimes out to 20mm, rarely wider. The only drawback is it's big and heavy.
15mm, even on the S35 sensor, is pretty darned wide for the stuff I do; I've only very rarely used it. Anything more than a few yards from the camera becomes pretty small at that point. So I personally wouldn't go for the 11-24. The 35mm end is something I use quite a lot. Of course for landscape stills, you might want the really wide look; I know I used to like having a super-wide lens when I was doing stills.
Having said that, don't write off the RF 35mm f/1.8 STM macro. That's a very nice sharp lens. STM means slow and loud autofocus, but who cares for landscapes. Also it's a pretty decent macro. But I would miss the ability to go wider.
The RF 14-35mm f/4L IS USM would be a lower-cost option too. I don't know about that one, though.
I've toyed with getting the 24-105 or the 24-70, which would cover most of my landscape work and also be versatile for other things. But so far I haven't really felt the need.
