Appreciate it. Hopefully, we can get this clarified and both learn something new in the process. I do know that box 7 income is SE with practically no exceptions. But box 3 income is "usually" se income paid for things like side jobs you do outside of your W-2 work for that W-2 employer. That work may or may not be related to your W-2 work, but the employer treats that differently. Usually as a way to get out of paying the employee overtime. I've also seen scholarships reported in box 3, where my above entry instructions would apply and be applicable for that. I'm curious to see how this works for you, if not as SE income as the IRS would consider it, based on the information we have so far in this thread.
