Amorim is going to have to learnly quickly that...
Garnacho isn't even bench quality for a title-aspiration team.
Fernandes will have to play as an "8", as he can't play as "10" in this formation, otherwise he'll take up a deeper position or start occupying the strikers position (circa Ole's tenure) 'cause he can't play on the half turn (which he admitted in a presser last season) and doesn't have ball-carrying ability. Amorim might already have that realisation cause Fernandes played as an "8" in the 2nd half.
Rashford can't be a starter as he can't play as a striker and has verbalised his displeasure in doing so on numerous occasions.
If he wants possession-ball as he's stated, then Amad as to be a "10" and Zirkzee has to start as a "10" or striker.
Either he'll learn or he'll feel... Time will reveal.