the title says it all.
Being better than Nene doesn't jump him all the way up to Rindou level, she gets the benefit of the doubt.
For now, Rindou win higher end of low-diff.
I'll give Rindou benefit of doubt since her style hasn't been revealed and she's got that vague thing with Eishi
I don't see Isshiki defeating Rindo. Isshiki is the best chef of the 91st generation. That makes him, at best, equal to the best chefs of 90th generation, if not lower(obviously only talking about the former/current Elite 10 chefs of their generations here, not average 2nd or 3rd years). Also, Rindo did not show any of her cooking, and she may be best chef of her generation, as well.
Being better than Nene who apparently failed vs Souma shouldn't mean that much