Two nations in one state? Yes, Biden’s proposal is not quite that, but it does suggest a path to that end. The way I would extend it is for Israel to take full control of North Gaza, quickly set up safe areas and hospitals, and after expurgating Hamas, invite those who have fled South to return to a region under Israeli control with full citizenship rights in a new state whose constitution provides for two “provinces”, one speaking Hebrew (and probably mostly of the Jewish religion), and one speaking Arabic (and probably mostly Muslim), with a polyglot ‘district’ (like the USA’s capital region) around Jerusalem which would remain forever under (and might become the new centre of) UN administration. The boundaries I would suggest are somewhere between the 1947 plan and the current reality, but some kind of local option would determine the actual boundaries.
Source: U.S. Presses Israel to Set Up Safe Areas During Coming Pause in Gaza War – The New York Times