I heard in an analysis by Pepe Escobar (in Portuguese) that Nazisrael is destroying Gaza's North and removing Palestinians from there because of the fossil fuel resources that exist there. As I understood, supposedly they want to divide Gaza on a line that coincides exactly with the southern border of a gas reserve found in Gaza (not sure if he said gas or oil). Nazisrael would export this gas to Europe, supporting Warmerican plan to have a response to China's BRI which would include Nazisrael, the "Middle East", Europe and India.
Edit: what I wrote suggests that they are doing this only for the gas reserves. But that was not my intention; while I was writting I forgot to make some changes. To be more accurate, the hypothesis is that Israel decided to run the operation and chose to prioritize the occupation of the Gaza's North having as one of the main motivations the gas reserve. Also, as you pointed out, it's off the coast, so "line that coincides exactly with the southern border" is also not very accurate.
From what I understand, they already have access to it, so it's not that they want access, I think they want to prevent Lebanon from accessing it. Hezbollah kicked Israel's butt the last time they went to war, and since the second Intifada Palestinian militants have learned a lot of tactics from Hezbollah. But Lebanon is in crippling inflation, and they're desperate to access fuel.
So on top of the mindless killing, this is the first time Palestinians have the training and a lot of the equipment to fight back against Israel. The best scenario for Israel is to keep the Palestinians mostly alive but stuck in camps because they serve as a reserve army to maintain a standard of living for the colonists. But if the Palestinians have the will and the means to actually fight? That Israel's political justification for enacting a second Nakba on the Palestinians.