expression, adverb, adverb taking the 'to' particle
this and that; one thing or another
Used to refer vaguely to various complaints, opinions, or details, often in negative contexts like どうのこうの言う (to complain about this and that).
彼はいつもどうのこうの文句を言っている。
He's always complaining about one thing or another.
細かいことをどうのこうの言うのはやめよう。
Let's stop nitpicking about every little thing.