Yahya Sinwar was declared the official leader of Hamas on August 6th 2024, following the assassination of his predecessor.

We will adjudicated based on who is the official Hamas leader according to Wikipedia.
https://en.wikipedia.org/wiki/List_of_leaders_of_Hamas

Consensus markets have about ~50/50 chance for current leader Sinwar to survive the year. But as you can see, Hamas has had only five leaders in its history, and only one of them had a short leadership...

If there is a dispute about leadership, we will wait for Wikipedia to resolve it, including retroactively, within reason.