My former Master's advisor is toxic, and we had conflicts. I cannot go into detail, I am afraid it will reveal who I am. I am an international student, and I earned a master's degree in the United States.
My advisor said they will write a rec letter for my PhD program. I am so afraid that they will write an unfavorable recommendation letter. I cannot control how my advisor thinks of me. Fortunately, another professor in the same department said they will write a recomendation letter for me, but they will not be able to say much about research skills because they are not my advisor, so they never have done research with me before. However, this other prof said they will write a favorable recommendation letter, because they saw how I suffered, and I impressed them in their class.
Is it a good idea to nevertheless also ask for a recommendation letter from my former master's advisor?