Resolution test results have been added to the Sony Alpha a1 review, a work in progress.
Here are some comparisons:
In these comparisons, more resolution results in higher image quality. There is nothing surprising about that. Also obvious, especially in the Canon comparison, is that the Sony Alpha cameras continue to produce strong moiré or false color.
Again, image quality commentary (and much more) for the Alpha a1 is available in the "Image Quality" section of the review.
Future Sony Lens Testing
Unless strong objections are voice, I will use the Sony Alpha a1 for future Sony Lens testing. While some visualization skills are required to compare against the existing lower resolution Sony Alpha a7R III test results, the difference seems relatively small from a lens comparison perspective.
If you are interested in purchasing my mint a7R III, let me know.