The only reliable eye af is on A9. A7 III is miles away when comes to eye af, EVF, tracking capabilities, white balance, etc. I had the opportunity to play with both at a recent event and I understood after a few minutes why the Sony photographer wanted to let go the A7 III and buy another A9 as a backup camera. Sony does an impressive job in adding features or improving the functions of their cameras and they are spending tons of money on marketing, hopping to get as much market share they can this year. That is good for us, consumers, because raising the bar means extra features for us.
As for "it is hard getting the eye in focus at f1.2 or f1.4 when comes to portraits", it is funny.
The only way to miss the focus is to use the focus and recompose technique. If I realy want to get similar eye af as Sony, I switch to live view and use dual pixel af with face recognition. It does a very good job in keeping the focus on the eye. Or use ITTR with me selecting the focus on the eye and let the camera track the eye. Or use lots of different tricks with any other cameras, no matter the brand.
And if someone is shooting portraits at f5.6-f11 and he is not getting the eyes in focus, then he really has to find another hobby.