For landscape I'd always prefer a FF camera with bigger pixels over the R7, at least for the classic approach with high f-stop numbers. The theoretical threshold for diffraction limited aperture (DLA) for the R7 is f = 5.2 (Bryan Carnathan has collected a nice overview list in his in-depth review of the R7
https://www.the-digital-picture.com/Reviews/Canon-EOS-R7.aspx). That means that already at very moderate f-stiop numbers diffraction blur starts to kick-in. But classic landscape photography with 35mm cameras starts with, say, about f = 10 minimum, up to f = 22 and more, to gain a maximum depth of field.
That said, DLA is fortunately a good-natured sort of image information loss, it can be "repaired" by digital sharpening in many cases in a way that it satisfies our visual perception, what is the benchmark of photography. But on the physics side of life, these losses are existing. You can say, of course, okay I render my images to sizes comparable to e.g. a 12 MP crop camera, like they were standard about 15-20 years ago. But with a FF body with bigger pixels and a good lens you can really catch more real details within the image frame when you close its aperture. That's why I often carry a FF body with me when I go out for birding, when I expect to find beautiful landscape sights, too. I still use my 5D4 OFV/mirror slapper, but of course for a FF ML body I'd prefer to have an EVF with more dots, too, since landscape is slow photography that allows you to set up your camera very careful. (Birding often is sudden action, and not always in settings where you can really control everything.)