It's clearly MichaelderBeste.
>extremely tactical and obsessive
>longest sustained number 1 spot in Showdown randbats by a wide margin
>held number 2 spot too at the same time with an alt account
>highest GXE of all time in gen 9 Showdown randbats
>held number 1 spot in every randbats generation at the same time
>countless tournament wins

VGC is not a real competitive format, since a lot of luck is involved. The greatest should be judged on sustained performance.