Would you care to speculate on when exactly Covid 19 most likely first arrived in the US and started spreading?

As if you’re Sherlock Homes trying to solve a puzzle.

( Speculating on when it arrived in other countries too like Italy and Iran is welcome. )

Seems to me Covid 19 already got out of China and started spreading several weeks even before that Chinese doctor discovered it and then alerted the Chinese authorities.

Chinese authorities reprimanded the doctor, then sat on it until left with no choice but to announce to the world of its existence.

In case you have been studying the timeline of the spread of Covid 19 with emphasis on geographics, can you please post links you have on it?

And as stated, pure personal speculations are welcome.