I am still using my 6D and for my mid-range I use an ancient piece of old junk...a 50 compact macro. Compact, and sharp for landscape. Canon has never come out with a replacement 50mm that interested me including the 24-70s. Nor do I want three zooms in my bag. Should I go to mirrorless I would continue using this lens because I still see nothing I would want to replace it with. Especially this lens! For the lack of a good and affordable 50mm lens I would consider going with Nikon. For all their lack of lenses, at least they do have a good 50mm lens, even if over-priced. Canon is coming out with a fine line of RF lenses, and it will be interesting to see what if any thing they do with a 50mm, and I don’t me the phenomenal RF50 f1.2, way overkill for landscape use, at least for me.
I am sure the new 24-105 is a fine lens for many users, just not one I would want.