TomD8, your very reasonable reply helped.
I deleted and re-entered the 1099-NEC, following again the same steps as before. The reason why a Schedule C and SE schedule are not generated is because I mark the income as having derived from a "sporadic" activity. If I don't check that box, Turbotax will generate Schedule C, etc.
So, all is good: Turbotax is doing the right thing, because sporadic activity income is not subject to SE tax.
My apologies for spending your time, and I appreciate your responses.
Kind regards
