You said Poland, Germany, and Russia should be the guarantors. Well, right off the bat Russia should be disqualified from that role. If there are to be guarantors, not only should they be neutral, but they have to be able to wield a big stick. That would mean the US, UK, and/or France from the West, and India and/or China from the East. China is as untrustworthy as Russia, and the US under the Democrats is unreliable.
Ukraine asked for the UN Security Council PLUS.
I don’t think they’ll even get the UNSC.
But they might.
As for US reliability, I suspect it’s because we have no interests there.
NO POTUS, past or present would go to war with Russia over Ukraine.