Was it an act of war against the world when the Chinese Government chose to suppress the truth about coronavirus, killing tens of thousands?

Absolutely, and they will have to be held accountable at the right time.

China wants lowered tariffs from the rest of the world and trade with China.  

At this time I am giving China the benefit of the doubt and classifying it as Reckless Endangerment .

Nope, it was authoritarianism at work. Nobody wants to give the boss bad news.
We had a similar problem here w/ Trump But, we have a free press and are lucky to have public servants like Dr. Fauci who forced the issue

i would hope not

The only person I remember calling the coronavirus a hoax was Dotard Trumpf.