Realistically that probably won't happen until there is a regime change in Russia. So, the best option for now is to keep giving Ukraine all of the weapons they ask for in order to maintain a stalemate and inflict as many casualties on Russia as possible. Russia has a large population but it's not unlimited; kill enough and eventually the civilians will march on the Kremlin. This may take years.

Ultimately it's up to the Ukrainians what terms they want to negotiate. But it would seem foolish to give up the option of joining NATO and the EU just to gain a temporary peace. If they're going to survive as an independent country rather than a Russian vassal state then they will need alliances with nuclear powers.