I have nothing against using prime lenses. The main advantage of a zoom is that I can walk around with a single zoom lens which covers most of what I want to cover for walking around landscapes, while still allowing me to choose a particular focal length to do a particular panorama with the same lens. When Canon comes out with more choices of primes that fit my needs I will probably get a few just for taking panoramas. But until then I'll use their RF 70-200 f2.8L IS for that.
Previously, I used an Olympus EM1_II, with their 12-100 f4 pro lens (24-200 f8 FF EQ). I could set it around 100mm (FF EQ) to take a good panorama, or around 135mm to take a really detailed pano (I'm talking a giga-pixel panorama or so here). It showed exactly the focal length in use so I could confidently get it where I wanted it so I could set the ball stops for the step size I wanted (I've taken some panos with up to 200 positions in the pano reliably set with ball-stops in both width and height).
As far as 3rd party lenses, if they transmit bad data about focal length then too bad for them and for the buyer who bought them. You live with what you buy, so why complain if you get extra information given to you that you didn't have before? If they identify themselves as a Canon lens then, again, you get what you pay for (cheap in, cheap out).
As it is, my very expensive R5 and RF 70-200 f2.8L IS lens can't report something as simple as the zooms current focal length which the lowly $1K or so EM1_II and $1K or so 12-100 f4 pro lens can reliably report. Too bad, Canon - maybe you should think about adding this in a future firmware update. After all, I'm quite happy with the really great quality of the images it provides, but they sure do have a few holes in their menu system features that should be examined, re-thought out, and fixed in future firmware updates.
