1. The system is designed for you to be able to climb your way up to Crystal tier quite easily, it achieves so with a combination of not allowing you to drop a tier and giving you extra stars with win streaks
2. A 50% win rate will not stagnate you, it will climb you very fast, a 30% win rate even can let you climb, those people who made it to crystal day 2 had a 70% winrate, which is absolutely unreasonable for most players
3. You might get sucky teammates in many matches, those are matches you are meant to lose, as even professional league of legends players can only attain a 70% win rate on a smurf account in bronze, it's the nature of team based pvp games.
4. If you approach these "loss tax" games with the intent to play as well as you can, and manage a close victory, you basically cheated yourself out of having to lose a game, which adds up in the end.
5. Player skill is largely irrelevant since the game is a lot more based on team comp rng, teammates rng and rng in general
6. Lastly, don't give up, it might take you 250 wins to reach crystal, but you will reach it nonetheless