Is it permissible to wear the niqab and an abaya with simple adornments—given the fear of not being accepted by colleagues and the gaze of professors—to avoid applying forbidden makeup, which is difficult to do without?

The fundamental principle is that women should be taught by women, not men. A woman must cover her body and conceal her adornment in the presence of non-mahram men. A woman should take the initiative to observe modesty and dress decorously, and not pay attention to the whispers of Satan or fear the departure of friends or the gaze of teachers. For whoever seeks Allah's pleasure, Allah will suffice him against the burden of people. The Shari'ah has not specified a particular dress for women in front of non-mahram men, but rather has set conditions for the hijab. If the abaya you wish to wear contains noticeable adornment, then it is not permissible to wear it in front of non-mahram men.