The interview process was fine but I ended up not getting the job and only know that because I got a generic HR email that they moved forward with another candidate. Nothing from the hiring manager. As an internal applicant, I find this extremely unprofessional.

The interview process is very professional and is a two way conversation to see if the fit works for both parties. It is a PAR based system to weed out lies so don't try to make up or provide theories, truly provide a situation that you have been in. It won't matter if you were successful or not as long as you provide steps you took to improve if you were not successful in a situation that you provide. No one is perfect and trying to depict yourself as such only hurts you.