So I was looking at this deck and noticed it says legal for competitive, but the commander is only white whereas the deck has almost all colors, how is it still legal if its breaking one of the basic rules, or have the rules changed in 2020 that I am not aware of?

Hey Daechon, this is something I learned just in the last year. As long as the Commander has for an activated ability, you can build a deck of those colors because the Commander needs those colors to activate their ability. Another example of this is General Tazri and Najeela, the Blade-Blossom who are also mono-colored legendary creatures but have activated abilities, meaning they're 5 colors decks. So in reality, no rules are being broken at all and it's perfectly legal.

Oh my gosh that is so awesome! Thanks for letting me know this!

Jodah, Archmage Eternal works this way as well.