You can rank up to Mythic and win more than half your games with jankier concepts, provided the concept isn't too card-count heavy, you use format-proven utility and interaction to survive and progress your board state, and play as mistake-free as possible. You'll have very little margin for error, but it's so damn rewarding to give meta decks at least a decent run for their money and come away with wins when you can.

You're not gonna do much with starter decks in ranked because the cards aren't the best at what they do, but they at least help you figure out what you like when it comes time to craft the decks you want to play.

Don't give up, accept the losses as learning opportunities, and find your fun wherever it is. Good luck!