Finding it hard to find a Master's thesis advisor in mathematics, all the professors I've asked say they are too busy
In your situation, one might advise that you better forget about the elite faculty members, now, and the mere struggle to work with them. There are two potential options in my mind.

Firstly, expand your professor set to young fellows and try to grab their attention. You will be able to flourish by the indirect guidance of the elite professors, as your co-advisor; but right now, delay within pursuing the thesis might be considerably harmful for you.

Second idea would be taken into account, if even young and inexperienced fellows at the department, corresponding to your desired research field, show no tendency for your supervision. In this case, you may have to switch from your current research interest, in an either partially or fully matter, to be capable of cooperating with the people, who are looking for any graduate student.