The most practical guarantee of security for western ukraine is for russia to have no reason to want to annex it. Once they've carved out the sweetbreads and left behind a welfare state, they don't need the rest.
The thing about "having western troops on the ground" is that its functionally identical to being a NATO member. If US/EU troops are (openly flagged) in Ukraine, then any continued war necessarily involves attacking US/EU troops which even if it doesn't invoke article V is still a direct conflict between nuclear powers. Its the same exchange. If the situation in Ukraine devolves, say a Nazi-led government takes over and seeks continued hostilities with Russia and resumes shelling Belgorod, how does that play out? Russia cannot let it go unanswered. Russia can't hit back without hitting US troops. The US cannot remain without being a direct party to a conflict. The US/EU troops could simply withdraw, sheepishly, looking like they are abandoning Ukraine and defeating the whole purpose of supposed peacekeepers.
Arming Ukraine to be a heavily weaponized state is even
more moronic and
less acceptable for Russia. Now instead of having US/EU forces trying to keep the borders stable and avoid conflict, you have a heavily militarized build-up on Russia's border posing a direct threat to them, with either an unstable regime or overt nazi radicals at the helm. FA pushes this like its a credible alternative. How many western weapons can be foisted on UA soldiers when they're all already dead, anyway? What, are we going to give them a nuclear deterrent, as if we don't all know how that ends.
Here's how you get peace in Ukraine: You sue for peace with Russia. You work out borders, you accept concessions, you put an end to the war. Russia will want Ukraine to be a non-threat to them, either demilitarized or not used as a NATO proxy or have NATO troops and weapons flooded into it anymore. Russia is willing to make a deal on those terms because its
what they wanted. Its unpalatable for the west because it means we admit we lost a war, but guess what, we lost a war. Will that peace last forever? Who knows. Will any threat of Russian aggression in the future be ended? Nope. You don't get the guarantees a victor would demand when you lose the war. You ask the other side to
agree to a peace, not force them to your terms.