Juventus is not ready to win the Scudetto title, they are still losing to Inter Milan both in terms of strength and level of concentration this season. Yes, I don't think they gave up, but they no longer have a chance to compete with Inter Milan. For this reason, Juventus this season is only targeting a top 4 place to play in the Champions League next season. As you said, Juventus needs to make changes to be able to compete next season because this season they are inferior to Inter Milan.
For second place, of course Juventus has the opportunity to take it back because for now they are only 3 points behind AC Milan and that is quite a close distance. For Allegri, of course, the target of finishing in second place is not their target for this season because finishing in 3rd or 4th place is of course the same, but the failure to compete with Inter Milan is certainly quite disappointing for them.
Of course, Juventus has no proper squad to compete with Inter Milan. Moreover, Juventus players often got injury. Now, Dušan Vlahović and Arkadiusz Milik are injured. Sadly, Dušan Vlahović seems to take a break for a long time because there is no exact time about when he probably recovers. Without Dušan Vlahović, I'm sure it is difficult to win in the big matches. So, it is impossible to compete with Inter Milan, specifically when the point gap is already very large. The point gap between Juventus and Inter Milan is 17 points now.
I agree that the realistic target for Juventus is to finish in the runner-up position. However, it is not easy because AC Milan is leading with 3 points now. Juventus wasted too many points, so AC Milan could overtake them in the 2nd place. With the current condition of Juventus, I'm not really sure if Juventus can return to the 2nd place again. So, the most realistic target is to stay in the top 3/4 (UCL zone).