Hardstuck Gold tank and diamond support player plays average in Grandmaster 2 lobbies

So it is really elo problem on my main or im just delusional? A gold tank diamond support definitely cant play average in gm2 lobby.

Support ganeplay: https://youtu.be/a\_GQdJOEBdg?si=LIkSE3i3d2W0mbIW

Tank gamrplay: K07P0J (Video upload tomorriw)

Proof: https://imgur.com/gallery/AxwBfhU

I am definitely playing not as good as gm2, but i think I am definitely way better than gold tank or diamond support, yet i played 400 games on my main still hardstuck, what can I do?