Help making a scaling score system. Then storing scale into potion level.

Hey so this might seem complex, but I am trying to find a way to take a randomized scoreboard value, (so random value 1-10 then take that and modify the mobs scale based on that number.
Then once I change that, how can I then tell the mob, to inflict poison of that level, so if the Scorpion scale 5 bites me I get poison 5? technically it'd have to be 1 lower cause Poison 5 is Poison 6 thru /effect give, can anyone help and teach me how to do this?
I'm in 1.20.6 for my project.
my commands so far:
execute at @s store result score @s number run random value 1..10```