I've been applying to doctoral positions in mathematics with a strong background. BSc and MSc in math, and a MSc in computational math/engineering. I've got research experience in my field and connected fields, a paper in preprint and more to come (with novel results), solid references, teaching experience, participated in international competitions representing my university/country, good grades. Still, most of the time I don't even get an interview. I definitely understand that there are people who are better than me, and I'm not mad about it. However, often when they publish who got the positions, and it can be someone who did their BSc over 6-7 years, or who had an adjacent degree (such as computer science or physics) but studied more mathematics, or who hasn't done any teaching or research otherwise.
A few professors I know have told me several times that it's not really fair, so what I have left are social skills. I just don't know what to say. I've had my CV, statement of purpose, application letters reviewed and they said it was really good.
How can I write an application that broadly speaking appeals to such a recruitment committee? What are some interesting forms of describing my ambitions? What catches the attention of a recruiter in terms of research ambitions? I have clearly stated my research topics, as well as why I want to do research in it and how, but I don't know how to spice it up.
Just to be clear, I'm in Europe, so I didn't drop out of any PhD program to get my master degrees. Also, most of the positions were open positions, so I just sent my application and then they will decide on what advisors should get new students.
EDIT 1: I'd like to clear out that I have a BSc and MSc in mathematics, and an additional MSc which is much more applied and incorporates a lot of physics and computer science. Thus, I do have the required courses to apply for a pure math position, which I even have checked up on on their websites.