en_tn/2co/11/18.md

many people boast according to the flesh

These people "boast" in the bad sense of claiming to be better people than they really are.

according to the flesh

Here the metonym "flesh" refers to man in his sinful nature and his achievements. Alternate translation: "about their own human achievements" (See: rc://en/ta/man/jit/figs-metonymy)

I will also boast

Paul uses the word "boast" ironically. See how you translated "boasting" in 2 Corinthians 1:12. (See: rc://en/ta/man/jit/figs-irony)