I couldn't say it better than @Bellum_Romanum Arms sales are of different nature than this visit. They are not an erosion of one china policy. They also don't signal support for formal Taiwanese independence.CN do nothing every time US send arms to taiwan but we are supposed to believe they will really escalate because of Pelosi ? Biden should just stop Pelosi from going to taiwan but should announce a big military shipments to Taiwan just after talking with Xi: Get something real for giving up something symbolic. Unless CN can deter US from selling arms to Taiwan, all this fuss about Pelosi visit is rather amusing
One China policy is more than a bunch of sentences written on a paper. It is a political compromise both the USA and China agreed to. By accepting One China policy, China indefinitely deferred its reunification with Taiwan. In turn the US ended its formal relations with Taiwan and recognized the PRC. So it is not appeasement of China as some harebrained Twitter accounts are saying. One China policy involves China tolerating foreigners interacting with Taiwan as long as they don't formally recognize Taiwan. It was a massive compromise by China. Taiwanese independentism is something that emerged later. In turn, a similar compromise was reached with Taiwan too. China was okay as long as there was no attempt at formal independence. I don't think China is going to allow Taiwan, the US or its usual allies to reframe it at their will. If the other side is not willing to compromise then neither will China.
China apparently views this as a very significant erosion of One China by both Taiwan and the USA. It will calibrate its answer according to this.