Depends on how you define success I guess.
If your definition of success is anything that remotely has to do with the well being of Gazans then its quite hard to make the case the Hamas attack was a success. Quite the contrary it seems to me.
If the goal was to kill Israelis, torture and humiliate them then yes it was a tremendous success.
>If the goal was to kill Israelis, torture and humiliate them then yes it was a tremendous success.
Which I'd argue is the whole point of what they are doing. That and getting the world, well, not on their side exactly, but on not-Isreals-side. Which they are slowly getting. I'd call this a huge success (for them - not for the poor people, of course).
The world is definitely a lot more on the side of the Palestinians now than before October 7. Israel has lost the public support around the world. Not surprising since it is basically committing a genocide against the people of Gaza.
Hamas have made it almost impossible for anyone to support _them_. There is plenty of support for the people of Gaza, but apart from Iran, no other state now dares to publicly voice anything other than rejection of Hamas' methods. That's distinct from the similar rejection of Israel's methods. Rejection of one does not automatically imply acceptance of the other.
Obviously their approach can't be seen as any form of success for the people of Gaza themselves who have now gone from chronic despair to acute despair. I don't believe that anyone could characterise how this has played out as a success for them.
Lastly, from a geopolitical perspective, even for Iran this can't be viewed as a win in the short term. Hamas' cold-blooded disregard for lives on both sides (and they _had_ to have know what the Israeli response was likely to be), means Iran can't be as overt and full-voiced in their support of Hamas (vs supporting 'the people of Gaza' or the Palestinian cause more generally).
Like I said, there's not enough info to be able to tell what the long-term implications will be yet, but in the short term this has been an unmitigated disaster. In my opinion.
The most successful in terms of outcome? Short and medium term, clearly no. Long term? TBD.