If we had to give an answer to “what makes you reborn” then the answer has to be the mind, as you indicated here.
From Abhidhamma, we know the description of “mind”:
hadaya vatthu + a set of pasada rupā
From this citta vithī flow (pasada rupā pinging the hadaya vatthu, making it vibrate), with each citta arising with a set of cetasikā.
For an arahant, cittā are pure, and the flow of citta vithī stops at the end of the arahant’s life.
For a non arahant ariya, cittā are “pure enough”, and citta vithī are abound to end after a certain number of bhava (depending on what magga phala it is).
For a puthujjana, cittā are contaminated to the point where there is no end in sight for the flow of citta vithī.
Isn’t this enough? Do we need to get deeper than cittā and cetasikā?