You have to accept the peace plan before you know what the peace plan entails.
Besides, the outcome is predetermined. All these names parties are in favor. The Palestinians reject it. So now what?
I was only being partly facetious. One of the problems here is that Abbas is aligned with Saudi Arabia, Egypt etc on the question of Gaza. Abbas wants Israel to toughen its stance in Gaza, to put a real blockade and starve Hamas in Gaza because they are his political rivals. Egypt has been a lot more amendable to Saudi Arabia lately, probably due to cash but in this case Egypt has no love for the Muslim Brotherhood/Hamas anyway. But Israel doesn’t really want a blockade of Gaza it just wants to inspect what comes in and out for contraband.
So for starters any plan that tries to unite Gaza with the West Bank will be rejected by Abbas. But without knowing more details it is hard to guess why the other states are said to favor the deal. There was suggestion last year that the deal would include expanding the territory of Gaza into the Sinai by 99-year lease from Egypt for the land. This would allow for natural growth and alleviation of overcrowding, and a construction economic boom would follow (Trump and Kushner’s specialty). But I am not sure if that is part of this plan.
And there is reason why Trump stopped all aid to the Palestinians today. Will that suspension of aid be followed by similar moves from some the other donors to the PA? I doubt the EU will cease funds but they have their own problems right now and can’t get too entangled with the Palestinian side. If Saudi Arabia and its allies go with Trump to deny aid to the PA, then this leaves Iran and its allies to fund Hamas. That puts enormous pressure on Abbas.