"Schedule Cs are audit flags and it seems like overkill to generate a Schedule C for a single 1099."

Except, that's not what you are supposed to be doing with this. The 1099-NEC was only issued because at least this one customer directly paid $600 or more for services. Your taxpayer should be reporting everything they made for their business activity, not just because of any 1099-NEC being issued. Your taxpayer could have earned $2 million, and as long as no one customer paid that directly as cash or checks to a total of $600 or more, then there would be no 1099-NEC. Does that mean your job is not to file any business activity at all? Of course not.

The 1099-NEC is called informational for a reason. That is not your taxpayer's business. That is your taxpayer's customer's piece of paper.

You're doing taxes wrong, if you really believe what you stated here.