"I have seen it discussed in detail, but is it true that all 1099-NEC or 1099-Misc gets entered on Sch C?"

As an observation, you will see older topics and discussions mentioning 1099-MISC, because 1099-Misc box 7 used to be for NEC. It is now reported on 1099-NEC (an old form that got reactivated). Keep in mind that now, 1099-Misc likely isn't a Schedule C item at all.

And you'll see all sorts of wrong info about 1099-NEC, for which limit triggers reporting, for how to report, etc. Don't watch TikTok.

The entire 1099 series is Informational. If your taxpayer has only private citizens as customers, there would never be any 1099-NEC issued, because that is a business-to-business form. Even if they made $3 million, there would not be a 1099-NEC. That doesn't avoid tax reporting.

For purposes of your topic, self-employed people should be tracking all of their business activity. You report all of their business activity.