I don’t think Likud and IDF leaders care too much about the wellbeing of the hostages, and their behavior pretty clearly reflects that.
What they do care about is international pressure, especially from the US. So if Hamas wants to maximize their bargaining power they should be seeking to undermine the public narratives around the necessity of the war. One possible way to do this would be the release of the hostages, which is constantly brought up as a justification for continued attacks on Gaza.
It would also be, you know, ethical but I guess we are past pretending they care about that.