The biggest blow Israel could deal to Hamas would probably be to do the minimum to contain them, provide the PA with access and means, and let the PA deal with it with guarantees of meaningful concessions if/when the PA succeeds in meeting certain targets (that ought to carefully not mention Hamas, but mention things like demonstrating a functioning justice system and ability to secure the borders). To your point of a "neutral" foreign coalition, if granted access by Israel, the PA would potentially be in a position where it could ask for international assistance and try to frame it as allies coming to the aid of the population rather than an attack on Palestine.
But that would also first take an Israeli government that is serious about peace and negotiating concessions, and frankly the current Israeli government seems as caught up in seeing the continuation of the conflict as essential to their own power as Hamas.
In the meantime there's a real danger this will stoke up more radicalism not just in Gaza but in the West Bank as well.
Has such a thing ever happened in history? I don't think it has, so it seems like fantasy. No one really seems interested in risking their or their children's lives policing some other group of people elsewhere in the world if they don't have some geopolitical interest in it.
Did you consider that massive civilian death could play into Hamas' hand? One of the insurgency techniques, where the action causes overreaction to amplify support ("action-reaction-revolution").
What happens in Palestine (a territory of the state of Israel plus the territories under the occupation) is called insurgency. To end the insurgency you can either withdraw, exterminate the insurgent population and/or convince the population to not support the insurgent.
Insurgency is always a fight for the legitimacy. The problem with this conflict is the fight for legitimacy happens not only between Israel and Palestinian Arabs, but also within these parties. Israel has official stance on supporting two state solution and un-official de-facto single state goal. Palestinians have Hamas, PLO, Islamic Jihad etc.
Israel has killed Hamas leaders who wanted to work towards peace [3]: >> After Israel assassinated Jabari, Reuven Pedatzur, a military analyst for the Israeli newspaper Haaretz, reported: >> Our decision makers, including the defense minister and perhaps also Prime Minister Benjamin Netanyahu, knew about Jabari’s role in advancing a permanent cease-fire agreement. … Thus the decision to kill Jabari shows that our decision makers decided a cease-fire would be undesirable for Israel at this time, and that attacking Hamas would be preferable.
An Israeli government that was actually interested in peace could halt and reverse the settlements in the West Bank, end the apartheid (e.g. military vs civilian courts for Palestinians, different class of citizenships, travel restrictions, prevention from visting Jerusalem's holy sites, etc.), the blockade of Gaza, etc. Treating Palestinians as humans (and not propping up Hamas) would likely go a long way towards undermining Hamas. Most Palestinians already didn't like Hamas - 70% wanted the PA in July 2023 according to the Washington Institute.
[1] https://www.timesofisrael.com/for-years-netanyahu-propped-up... [2] https://theintercept.com/2023/10/14/hamas-israel-palestinian... [3] https://theintercept.com/2023/11/17/hillary-clinton-hamas-is...