Sony a7 IV vs Canon EOS R6: Which is the best enthusiast mirrorless?

Introduction Sony's a7 IV is the company's latest enthusiast-targeted full-frame mirrorless camera. Its price and spec put it directly into competition with Canon's hugely likeable EOS R6. The improvements to the Sony mean that both promise powerful combinations of image quality, autofocus and video capabilities. But which is the better camera? Given that the majority of modern cameras are very, very good, it's unlikely to be a decisive victory overall, so we're going to...