I'm doing a master's degree in theoretical physics in Europe. After the end of the master, I want to pursue research in the area A. In fact, I've already come in contact with a professor that works in the area A in a different country.
The problem is, I'm struggling to find an advisor for a possible master thesis about the field A. I contacted roughly 6-7 professors at my university already and they either: 1) are too busy and don't want to start a new project, or 2) are not interested in what I want to do because they only accept projects strictly related to their recent research interests, or 3) don't answer my emails (after 2 weeks of waiting).
I'm considering to accept a master thesis in a different area B due to these reasons.
How would it be seen from the point of view of a prospective PhD advisor?