Possible. More likely the equivalent of German soldiers in Polish uniforms attacking a German radio station...
What would they gain from it? Russia is already doing everything it can do against Ukraine.
It seems like this would be more of an embarrassment to Putin, and a confidence shaker to the people.
Well, here is support for your idea.
Has Russia carried out a FALSE FLAG ‘assassination attempt’ on Putin? Ukraine denies Kremlin strike drone was theirs - as Moscow rages Kyiv ‘must now be DESTROYED’
https://freerepublic.com/focus/f-news/4150366/posts