This datapack implements random number generator functions to get numbers from easily customizable ranges (customizable inside the datapack). (has examples inside as well)
TO USE:
function rng:rng/0to8
execute if score RNG rng_global matches 0..2 run # your function

I made this datapack since i couldn't find a good datapack anywhere else for this, although natural_power did come close but made biased rng.
My performance is actually good unlike the bad ones, that just crash my game when i run it 65,536 times.
Mine takes about half a second to run it 65,536 times.