So in the survey there is a question "rep_name" which is a single answer list question with around 50 possible responses. At the end of the survey, the respondent enters their name, phone and email. I want to send a message to an email that corresponds with "rep_name" (so there's around 50 possible email recipients.)

One thought I had was to create 50 surveys that just asked the contact questions, and then have lime survey chain from the main survey based on the answer to "rep_name" (not totally sure how to do it.)

I am looking for options and flexible on how it happens.

I think with an equation question and the administration email option you should be able to do this.
I would create a equation question that check the "rep_name" question and writes the email of the chosen rep into the question. In the admin email option you just put the code of that equation question and it should send an email to that rep.