I am not pro Trump but there are huge amounts of Chinese pro Trump. I think the number is even more than pro Biden. The reason is that though Trump will continuously anti China, but he will do much more harm to US democracy, tearing up the US society and hurting and losing allies especially Germany, EU and South Korea. US will fasten the speed to give up the role of world leader and you guess who will grab the opportunity. Comparing those pros and cons, nationalist Chinese generally prefer Trump.
Those support Biden have the same reason as the rest of world. We want a more predictable world for financial market, industry, imports and exports etc. We want a stable life based the old world order not based on personal bias.