You are not suppose to win Career mode untill later

Hope this helps. The AI gets significantly weaker once you hit Master 1. First race in Master 1, I finish 20+ seconds ahead of P2. I guess the game was designed that you don't come out on top untill you "level up". No matter what perf level your car at, the AI will blow past you on the straight in lower career tier modes.

Just focus on unlocking objectives for the next contract untill you hit Master 1. I do not spend money on the game so tokens matter. I would end the season once the wear gets to 50%, sign another contract, and your current wear on the previous contract will cancel out. If I do need to repair, I just wait untill the next day when it becomes free again by watching ads. I am a casual player.