Do a lot of day hikes and typically I go from shooting animals to landscapes as we go along.  I don't like switching lenses on the "run" so bring my A7RIII with the Sony 12-24mm on it for landscapes and the A7III for animals with the Tamron 28-200.  But when shooting smaller animals I miss the megapixels to crop when shooting A7III.  Switch or just deal with it?

When I'm hiking, weight -- and the nuisance of TWO cameras around my neck -- mean just one camera and one lens.  But I usually have a pack as well.  If you are comfortable with two cameras, I'd use the A7RIII for the animals so you can crop.

Otherwise sell the A7III and get another A7RIII -- or get used to swapping lenses.

I think I agree with XKAES, to have the 7Riii with the long lens - to allow for cropping and the A7iii for the wide angles.

If you then see a landscape you want a high def image of, you can always take your time to switch your wider lens to the Riii, but doing it the other way (as you do presently) I would have thought you might miss the shot if you feel you need to switch lenses.