An assassination of Vlad and how it would playout has been discussed prior to the Ukraine situation boiling over.
Vlad is an idealist who very much desires the glory years of the Soviet Union. He detests the oligarchs who thieved their way to riches. Sees them as having stolen the Soviet people's assets and accelerating the collapse of the 'once great nation' into the abyss of chaos, in order to gorge themselves.
He is not wrong on these points, but he has a mutual business relationship of convenience with them, where he lets them do what they want, as long as they endorse and stroke his power. It's an uneasy relationship, not overly trusting. Much of the oligarch's wealth is hoarded in offshore banking havens and in London. If the NATO nations were able to orchestrate a freezing and or confiscation of the oligarch's wealth and financial resources, it could stoke an internal feud (reminiscent of the internal feuds in the chaotic 1990s) where the oligarchs have Vlad assassinated. Not because they have any altruistic care for the people of Ukraine. Just that their wealth would be wiped out. These are extremely narcissistic people who only care for their own riches.