expression
now, although it is too late; at this late hour
Expresses that the speaker is bringing up or realizing something belatedly, often with a sense of embarrassment or irony. Used adverbially at the beginning or middle of a sentence.
今更ながら、そのことに気がついた。
I realized that now, although it's too late.
今更ながら、彼の才能に感心した。
Now, belatedly, I'm impressed by his talent.
expression
Used when re-examining or re-experiencing something with a fresh perspective, often implying that the speaker should have noticed earlier. Less common than sense 1.
今更ながら、この映画の素晴らしさを再確認した。
I reaffirmed the greatness of this movie anew, though belatedly.