The problem is NOT that the game is massively broken (like you suggest), but that there are players who are just more skilled than you. For pretty much every playstyle there is a counter that’s why there is no deck which works against everything else.
And also: Losing is part of the game. Remember that everytime you win somebody else has to lose. So if you win more games than you lose there have to be people who lose more than they win. That’s just the nature of a multiplayer versus game.
Losing is super frustrating, but winning is extremely rewarding.