Some people proposed to use
InDesign or Illustrator
Any idea on how to do it using Dorico only?
That’s the way I found but I would prefer not to have to use
a pitched notes on the system and use something with text at the same level as the chords are written.
I’ve never seen anything like the chart your friend produced and I would have to guess what it meant. It’s not at all standard.
In jazz charts, it’s normal either to put the chord in the correct position rhythmically or to write some notes that suggest the timing.
In your case, as it’s a lead sheet, I would simply put the Db / Eb over the quaver rest, if that’s where you want it, or leave it where it is, if that’s where you want it. There’s no need for anything else.
Is this a Latin arrangement? If so, you don’t need to indicate the basic rhythm patterns - the style will tell the player what’s appropriate.
Yep, and left-align your chord symbols, don’t center them! Is that first Dbmaj7 on 1, or on the & of 4 of the previous bar? It’s unclear when centered. If you left-align your chords the rhythmic starting position becomes clear and there’s no need for any of those unnecessary markings.