You're going to have to cite that, because Ukraine was already in the low-intensity Donbass conflict when the most recent invasion happened.
But yes, you can't hide an invasion fleet. The Chinese navy only has three aircraft carriers. They've recently had high level purges in the PLA. Invading now would be a disaster for them. But you never know when a disaster is going to get ordered for political reasons.
In terms of gaining political support, being a victim in the modern world is very advantageous. The more of your civilians die unjustly, the more the media will portray you as a great and brave leader. There is nothing hilarious about this, only cynicism of the leaders of the country.
Not the full truth. Leadership said publicly that there was nothing to worry about, but the AFU dispersed assets, distributed suppiles and ammunition, and took a defensive stance before the invasion happened.