I don’t agree with your interpretations of the terms accent and dialect. I think it needs more linguistic expertise to find a good approach.
And to be honest, I am more than sure that people at linguistic departments in many universities worldwide would be happy to help. Collaboration efforts like that could fill a master’s thesis for a student in linguistics and the Common Voice project could benefit from real expertise in questions about how to grasp the varieties of languages.
My personal suggestion would therefore be to support what has been brought forward in the second post.