I am from a poor country in Asia . I will apply for PhD positions in pure mathematics in USA in the upcoming year. I completed my masters in mathematics in June 2020 but I am still not able to find a PhD position. I am not applying for PhD positions in my home country due to systematic racism by seniors and peers in my masters and bachelors. It is heartbreaking!
My masters thesis advisor never replied to my e-mails after giving me a research paper to study. She was from another institute than the institute from which I did masters and I contacted her because no one in my institute was specialized in the branch I wanted to study further. So, I did my thesis by myself and got 9 grade out of maximum 10. I visited her institute in January 2020 and she gave me a research paper to study and after that she never replied to any of my e-mails or calls. It was very much stressful.
I have learnt on this site only( I was reading some old posts about 6 months ago) that if someone doesn't has a recommendation letter from their master thesis supervisor then it can be very difficult for them to get a PhD admission( It is considered a very big red flag), much less in a country like $USA$. I can take a recommendation letter from a professor who taught me in Bachelors degree and she taught me 4 different courses and she replied in affirmatively that she can write a strong recommendation letter.
So, should I consider applying to USA, Poland and Chechia without having a recommendation from a master thesis advisor or it will be a complete waste of time?
Kindly let me know!