That... doesn't make sense.
You can be the greatest Scrum Master in the world, and your team could still deliver below expectations, because you can neither influence their actual work, nor the expectations.
You have zero influence on how well people perform in their actual job. Just compare a team of 5 senior widget makers to a team of 5 temp junior widget makers under the same Scrum Master.
If the senior team performs five times better than the junior team, your job as a Scrum Master is to make that transparent and visible. Your job is not to train those juniors in their job functions! You are the Scrum Master, you do not need to be a better widget maker than the teams widget makers. Your job might be to facilitate discussion in your team what they need to become better widget makers. If that is training, it might be your job to go up on the ladder and ask for training.
So, again, this criticism does not make any sense, nor is it in any way actionable, because nothing you have the power to do will make your team produce more widgets.
If you are a Scrum Master, you should not become a leader. It's not your job to lead your team. It's your job to help your team organize itself.
What can you do? Well, this is not a project management topic. You might be better served asking this on The Workplace. But the short version would be, show what you do today with your team to improve. Ask other Scrum Masters how you can do better. Ask your boss what specifically they expect from you to do better. If they insist that despite it not being your job, you are still judged by the performance of your team, not your performance of being Scrum Master for that team, ask for a better team or find a better job.