Welcome to the Wefugees Community and thank you for your question.
Indeed, as long as your asylum case is not closed, you can not apply for another residence permit. But as soon as you are formally able to apply for a residence permit, you don't need to be afraid to get it granted, as far as I know. You might find alla_fka's last comment in this thread also useful.
Without knowing your personal situation, I was just thinking that your lawyer apparently sees a chance for you to win the case in court.
I will link our dear @alla_fka here again. Maybe she can share another thought on this.
However, please feel free to get back to us with any further question.
All the best,