Extra context is that it was not only ''Hamas shall disarm(and some other fraction) that was reportedly agreed upon, there is also some new to be formed ''security forces'' with an interim government where Blair all of the sudden would have popped up(thankfully it's widely reported he is out of the picture), the agreement was these forces where to replace Hamas, and Hamas agreed to dismantle their terror tunnels, lay down their arms etc.
The Peacekeeping Force and Governance is taking time (it never is a quick process) and faces particular challenges in this situation.
There needs to be a legal basis. 3rd party countries are never going to send in troops without some legal authorisation and rules of engagement. That means the UN who Israel reject (and UN would need UNWRA which Israel rejects).
Rules of Engagement become crucial eg would these Peacekeepers fire on IDF troups when they start killing civillians trying to get to the ruins of their houses? or would the Peacekeepers only be allowed to fire on Palestinians (effectively taking the role filled by the IDF in the West Bank)?
And then you've got to coordinate loads of troops from different countries who use different kit and don't speak a common language as well as feed and equip them when Israel is blockading the area.
Israel is already getting fussy rejecting offers eg Turkey has offered but Israel is rejecting them as Erdogan has been critical of their behaviour.
And the Governance again needs a legal basis, Trump & Blair cannot unilatterally appoint themselves to govern the region and command these 3rd country troops. Needs the UN and US/Israel at best despise the UN.
Given Israel has no intention to pay anything towards all the civilian damage they have caused, no other country is going to start contributing for rebuilding unless there is a solid legal basis for a stable long term governance. They'll need a lot more than a vague uncertain ceasefire document without timescales. And they'll need confidence Natanyahu won't just ignore Trump tomorrow or that Trump won't completely U-turn after watching Fox News this evening.