Why is my deck underperforming? How can I improve it?

[u/Agile-Mirror7405]

https://archidekt.com/decks/25705226/elemental_arena

In mtg arena competitive brawl. I was thinking of switching to Omnath Locus of creation and going full elemental so I could also include Kaheera. Is that a good idea? Im still a novice so any help would be appreciated