Sancho has 34 key passes in the PL this season (2.10 per 90 mins), resulting in 2 assists. His expected assists is 2.45.
According to Understat, he has created 6 chances with an expected value between 0.10 and 0.16, then 0.27, with his highest being 0.39 (to Weghorst).
9 of his key passes were for long range shots, another 3 for shots just outside the area, including his assist for Fred's deflected goal against Spurs.
His assist for McTominay's goal against Everton is also fairly typical of a type of key pass he contributes, a shot inside the area but at an angle so difficult to score. McTominay's goal was the 6th highest value chance that Sancho has created in the PL this season.
Garnacho has 2 key passes in the PL, both assists, from huge chances, expected value 0.41 and 0.70.
Elanga has 6 key passes in the PL this season, one assist, two huge chances, the assist for Sancho's goal against Liverpool, and Fernandes' chance in the crazy minute at Southampton with an expected value of 0.66
For expected assists per 90 mins in the PL, Fernandes is top, then Elanga, Garnacho, Eriksen, Martial, Sabitzer, Fred, Casemiro, then Sancho at 0.15
For key passes per 90 mins, Fernandes top, then Sancho, Fred 3rd.
(all figures from Understat)