There is another way to offset the advantage the A1 has over the 24MP sensor of the A9 II
relating to cropping only, and that is as follows: use longer lenses on the A9, specially ones with wide apertures. These lenses are a lot more expensive, but with apertures of at least f/4 you still can double the focal length using a 2x extender-if needed. Also, most of the money will be speeded on lenses, as long as you want the best. The body loses a lot of its value a year or two later when the need model arrives, but the price of the lens remains constant.
Even with the A1, Sony still has to nail-down the eye focus and tracking on both video and still photos, and I am certain that Sony will solve that issue very soon.
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That said, I seldom use the fastest electronic burst mode of my R6, because it takes hours and hours in front of a screen to view so many images. But then...I am not a professional photographers taking pictures of small and very fast birds in flight
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Instead I use the mechanical shutter at medium speed, and sometimes at 12 fps. How fast are the burst modes of the A9 II? And how good is eye focus/tracking?
And guess what? So that you know, I do dream of the 45MP sensor on the Canon R5 sometimes.