It's a truth universally acknowledged that Putin lies and lies and lies.
But in spite of doing it all the time, he's no good at it. He might at least cover it up with a few non-controversial facts. But he can't. He just comes straight out with nonsense.
Only a Russian is gullible enough to believe him. And many Russians only believe him because if they don't they will end up in a prison camp.
He invaded Ukraine because he's a megalomaniac criminal who wants a bigger empire and needs gifts to give to his corrupt oligarchs. And so he attacked Ukraine. It's simple.