AKK as CDU chairwoman is still the default option, but she is in a relatively weak position. Other names that would come to mind are:
Merz (CDU, to the right of Merkel)
Laschet (CDU, about similar to Merkel, I would say)
Spahn (CDU, arguably to the right of Merkel)
Söder (CSU, to the right of Merkel, but steering towards the center)
Habeck (Greens, should the Greens become stronger than CDU/CSU or in the unlikely case of a GR2 majority)
All in all I think that NRW governor Laschet could be it, but who knows.
AKK already is chairwoman.
It's about the next Chancellor (candidate).
I meant "AKK is the chairwoman and hence the default option".
Do you think it is possible that the CDU elects a Chancellor candidate other than AKK and then replaces her as CDU-leader as well with that person ?
Good question. Chancellor candidate and chairman have always been much more connected in the CDU than e.g. the SPD. Therefore nominating a different chancellor candidate than AKK while at the same time keeping her as chairwoman would be difficult. The SPD has done this several times, but the CDU ("Kanzlerwahlverein") not so often.