If Ukraine stalls the attacks and prevents a takeover I hope countries take note of how to fight a war that is not in your country. Let the country being attacked fight on their own but provide them with the supplies they need to win. We helped Iran, Afghanistan, Iraq, and several other countries, within 20 years we would be fighting each of those countries.
After 6 weeks the Taliban was about to surrender to US special forces that were assisting local groups like the Norther Alliance. Once we brought in conventional forces like Russia did there we were done. Sending advisors and the like to Ukraine is the best way to go for everyone and would keep up distance from Russia saying we created an act of war by sending in troops