You can always count on PMR to be confused and confuse everyone else.
This video makes no sense as he is confusing two things.
First of all the first setting he turns to OFF which he claims is new to the A1II is on his A9III. So this isn't new at all. That first setting just disables all subject detection. If you turned this off for bird photography there would be no bird af/eye af running at all.
The second thing he mentions is the only thing new in the A1II. By default (I assume) the A1II runs in the new Auto mode. PMR is probably correct in that you should not run Auto and instead select the proper subject (in his case humans). For us we would want Bird.
However, by turning off that first setting (subject recognition in af) he is turning off all subject detection so it really doesn't matter what subject he has selected.
So he is either saying that Auto subject detection isn't working but Human is and therefore he should leave subject detection on and change from Auto to Human. OR he is saying that even Human isn't working and then he should turn subject detection off. But as long as he isn't using Auto he should be able to use the same settings he has been using on his A9III the past year. If you go watch his A9III setup video he has Subject detection ON and set to Human. So I don't get why he is so adamant to turn it OFF in this A1II video???
On my A1 I do have a button programmed to toggle Subject detection on and off because sometimes the BEAF is grabbing some other dark spot in the frame and not an eye and won't let go so it is useful to turn it off for that scene.