An odd concern to have.

Have you spoke to any Ukrainians, and are you aware of the some of the crimes Russia has committed? They've literally spirited off thousands of children and re-homed them inside Russia. The level of hatred the average Ukrainian has for the average Russian is almost at the Holy War level.

Not an odd concern at all.

Our posture towards Taiwan is one of "strategic ambiguity" - a strong enough commitment towards defending them that it has dissuaded China from attacking, but one that's subject to enough US discretion to dissuade Taiwan from declaring independence (much less declaring war).

So...the "strategic ambiguity" argument goes against allowing the Ukraine into NATO. After all, if a "will they or won't they approach" is good enough for China - who views Taiwan as a runaway province and doesn't even recognize Taiwan as a country - then why wouldn't than be good enough for the Ukraine?

It's not hard for even modestly skilled diplomats to craft a policy that would signal to Russia that aggression against Ukraine will be met with an overwhelming flow of resources and materiel for them to defend themselves, and also signal to Ukraine that if they get into a conflict that they started that they'll be on their own.

Indeed. Which is why NATO membership is not necessary in this case. A mere statement that "A whole, sovereign and prosperous Ukraine in the long term interests of the United States" would suffice.