You asked
Sony a7cr vs sony a9 iii?
The a7CR is the one for detail. It has 61 megapixels in the small a7C II body, plus in-body stabilisation. The a9 III has 24.6 megapixels, but it's the first full-frame camera with a global shutter, so there's no rolling-shutter distortion when you shoot fast action.
For landscapes, portraits or studio work, I'd pick the a7CR. For sport and wildlife, the a9 III is the better tool.
Both take the Sony FE 70-200mm f/2.8 GM OSS II, which is a strong choice for portraits and sport. For an everyday walkabout zoom, try the Sony FE 24-105mm f/4 G OSS.
Written by Claude from this site's pages.