Youtuber Jared Polin has posted the full review of Eye AF comparison on Sony a7R IV (B&H/Amazon/Adorama) and Canon EOS R5 and Nikon Z7. From the result, we can see that Sony a7R IV has very similar eye AF performance as Canon EOS R5. You can take a look at full review above.
The Sony a7R IV is the latest full frame mirrorless camera from Sony, it has a ground breaking 61MP full frame sensor. Here is a quick specs comparison for Sony a7R IV with a7R III with Nikon Z7 with Panasonic Lumix S1R. You can take a look at full specs comparison here.