There’s no way anyone can know that without a full and transparent investigation being done, which Israel did not allow to happen.
That said, there are many indicators that they did a significant amount of damage.
One example:
All the burned bodies and cars from the festival that were somehow burned by Hamas (with molotovs?), and definitely not by Apache helicopters equipped with hellfire missiles. Oh… except for the handful of bodies that turned out to be Hamas fighters. THOSE ones were killed and burned by hellfire missiles, but the Israeli bodies were burned by Hamas. And so were their cars of course. Let’s not worry about why the cars were trucked off far away, shredded, and compacted before being buried. Definitely has nothing to do with making it harder to investigate what actually happened to them.
Much of this info has been available for over a year now.
That’s my belief versus the mostly confirmed accounts that are based on limited evidence.
Describing it as factual was my mistake, but I did so because of how incredibly likely I think it is.