Some sentiments I see from the Chinese side:
For a lot of people, it's the first time they've been able to directly interact with foreigners and make use of the mandatory English classes that they've been taking since elementary school
This is a special in moment in time, where the people in both countries can just converse and see just how similar they really are. Many people are staying up late to really get the most out of it because we don't know how long this can last
Lots of misconceptions being corrected, including but not limited to: Americans don't get period cramps, Christmas and Jesus are Korean, all Americans have big houses like on TV, work in the U.S. is easygoing
Finding similarities between parents, like asking if they're digging a hole to the U.S., or saying that when they were little they had to walk uphill to school in the snow both ways
Two things they were shocked by: cost of university (in China, the better the school, the less you pay), and learning about rural food deserts in the U.S. ("aren't they farmers?")
Lots of comparisons on the cost of rent/groceries/medical costs/salary/work hours etc, with the resulting sentiment that the common people everywhere really are the same and have a common enemy
Lots of them have changed their typing habits so that it's easier to machine translate and are now stuck with a sort of "translation accent" in their Chinese from reading so much machine translated Chinese
After the Americans joined, the quality of the posts have gone way up ("Rednote algorithm knows there's guests here and so is serving the best dishes now" / "Why has Rednote been hiding the good stuff? The guests are worthy but we aren't?")
Also there was a post asking Americans to post pics of their work lunches, but I think the Chinese users might've been disappointed by the comments, because half the comment section was pictures of empty hands ("Didn't have the time") or like. a cup of coffee