no to WW3
Any assassination of Putin, would only come from within Russia and would have to be supported by the Military. Who would blame the West/Ukraine for there own internal media propaganda, and would not immediately end the war in Ukraine.
What happens after that depends on How the West...
but if you were Raheem on 300k per week, you surely would only go elsewhere if offered more!, or quite happily sit on the side lines earning money for nothing.