fair play; Problem is you mentioning it is not only to be used in real time, but also to then be looped. It will need something to base itself on, a time scale, right ?!? your note might be half way the measure you wanna use, might be 3/4, etc. Otherwise wont be able to loop it. Plus on a live performance we all know how much it varies throughout the track. Get me?!?
And if you saying that about the DAW's i mentioned, then u need to dig deeper into them. You are talking to a music producer , but also as a live musician .
Either you not getting what im saying, or im not explaining myself right ( which i think i did already).
Now if you tell me that your band plays live with a metronome( that can send a MTC to the arduino) then things are different