You're talking about one-offs and issues which were logically explained or corrected. You misunderstood or more likely misinterpreted the xenophobia comment; not going to waste time with that. WHO reported on Jan 5, 2020 so that's the starting point for a president of the USA or at the least Jan 10th following another WHO announcement.
As for Chinatown, you're drinking the wrong stuff. Trump claimed she said ""Let’s all have the big parade — Chinatown parade.'” Pelosi didn’t say that. In fact, that parade had taken place on Feb. 8, more than two weeks before Pelosi went to Chinatown.
From NPR: As for the coronavirus, Pelosi didn’t deny its existence — contrary to Trump’s remarks — while visiting Chinatown. She struck a middle ground. “Prevention, prevention, prevention. We want people to be concerned and vigilant,” she said. “However, we don’t want them to be afraid.”
During her excursion, Pelosi was asked if it was irrational for people to stay away from Asian-American-owned businesses in San Francisco and elsewhere.
“Well, that’s one of the reasons we are here today,” she replied. “It doesn’t make any sense, but it’s not just Asian-owned now."
Note that at the time no quarantines had been imposed in the US, people were still going out. What Speaker Pelosi was doing, in fact was asking that people not discriminate against Chinatown.
As for the Travel Restrictions, they were not a total ban in fact. https://www.factcheck.org/2020/03/the-facts-on-trumps-travel-restrictions/