Get some blues in ya 2, 5, Ones!

Here is a 'normal' kind of ii V I
...incorporating blue notes/passing notes on the 'downbeat'.

The downbeat can be considered the moment where the chord lands.
Which might in fact be an off beat,
but - if the chords are implying a polyrhythm, then it's a down beat in that rhythm.

In the D-7 chord the Eb and the F# sound fine - because it's a definite jazz lick in C.
So straight away the ear hears the blues and the key of C -- and the chord being a ii chord.

Note on the turn around chord A7 the last note is Ab in the phrase.
Here is a classic example of making the chords fit the melody.
I just wanted to play Ab at the end. And then realised that that's fine; of course the A7 could be Eb7 and to me a seven chord with 4th in the melody is very bluesy.

PS. This is easy to get your head around in C. But if you do it in E and A, B, F#, Db etc -- then you will really be properly mastering you ii V ones. You have to learn how to play bluesy on ii V ones in all keys.