I do think they were slightly involved. They invested a few billion dollars into pro-democracy organizations inside Ukraine, starting in the early 1990s, and held close diplomatic relations with Ukrainian politicians. None of this is abnormal, it's the standard practice of US soft influence.

But it's not even close to an exhaustive explanation. The Ukrainians have agency, they have their own media ecosystem, they are capable of forming their own opinions. They saw Putin as the dictatorial thug that he is. Putin achieved that by himself by invading Georgia, poisoning his opponents overseas, rigging elections and assassinating journalists.

Anyways, this isn't relevant to the question of Putin's rationality.