for like the last 2 expansions i’ve basically have only played against either plaque dks or now rainbow dks. (last week though i got some variety in 1500000 wheel warlocks). It’s just draining to only play against one deck right now in low diamond.
Seems your subconscious would like to play Wild 
The solution is simple: play with your friends. Everyone agree on what decks are allowed and what decks are not and voila, variety. If you don’t have any friends, no problem, create a thread where you talk about game between friends using a variety of decks and ask people to friend you. And if they don’t want to join, propose some rewards for those who join you. For example: you can buy packs for everyone that joins your meta.
i have some homebrew decks i like to play in casual when i get tired of ranked. i go up against many different kinds of decks there