As things progress, what I understand is that Netanyahu and Israeli National security apparatus and even USA knew of the possible preparations. What if this is designed from start to level out Gaza. The timing is very important. After the formal announcement of IMEA economic corridor. It is very relevant for UAE and KSA for their post oil economy. Since it uses Israeli territory and port to access meditarenian sea, Israel would've definitely demanded their hafta. Also note that India - another member if IMEA was extremely quick to call it out as a brutal terrorist attack. UAE, the other member, very softly blamed Hamas and Palestine.
To say that the preparations for such a large scale offensive by Hamas went unnoticed by Mossad and CIA is not believable. Reports say Egypt already alerted Netanyahu 1 week back