SNL isn't improvised. Also I've never heard anyone claim Pete Davidson has improv ability.
The writers change up the script until the last second, anyway, so the players are usually just as surprised at their lines as anyone.
As a recent example, "Lisa from Temecula", there was much discussion whether Ego's retort "oh, cuz we Black?!" was improv, and also, as a sketch that was nearly cut from the lineup, they decided to run it with a hilarious shaking table, which was the source of Pascal's surprise and laughter, and infectious to the rest of the cast.
This article [2] says, “Oh, ’cause we Black?” was added ahead of the run-through, but camera direction changed and not everyone was informed who the camera would be showing as it was delivered.
[1] https://www.slashfilm.com/1225418/why-lorne-michaels-doesnt-...
[2] https://www.vanityfair.com/hollywood/2023/02/snl-lisa-from-t...
Improv players are in a good position because being able to create comedy in the moment (improv) is a good proxy for being able to create comedy over a week (SNL). Writing is so important to SNL that players must either write themselves or partner with a writer to get airtime.
Some of the best moments were improvised, for sure, but they're not planning on it (obviously) and they're not depending on it. The sibling comment said enough about that.
> The writers change up the script until the last second, anyway, so the players are usually just as surprised at their lines as anyone.
Yeah, it's written. They're reading the lines. Not improvised. Obviously they're bringing creativity to it in their acting, but they've heard it in pitch meeting, they've contributed to writing it, they've heard it at table read, they've heard it at dress rehearsal, maybe a line on the cue card has changed.
There are moments of improvisation, but SNL is emphatically not improv.