No need to be aggressive. I was thinking about the "Kissinger consensus", if you like, which was how the State Department worked for decades when dealing with Taiwan. Or even just the softly-softly approach of the Obama years.
But surely China's foreign relations need to take account of the fact that many countries around the world are multi-party democracies where governments and policy changes, so it's not practical or logical to interact with them as if they were a one-party state like China. If Xi is President-for-life then it's fairly easy to say "you did X, our future position is therefore Y". But to say to Biden "Trump did A, our future position is therefore B irrespective of what you do" takes away any possibility to improve relations. That could work with a small country like New Zealand who could be pressured into adopting a submissive foreign policy posture, but it's unlikely Biden will just do what Beijing wants on all the important issues simply because of Trump.
2021 is a single opportunity for China to reset relations with the US, even if it may not be possible on all fronts. One of the attacks made on Biden was that he would be soft on China. It's probably not true but he will probably be less confrontational so it would be worth engaging in an honest fashion. That is an opportunity for China. But to effectively respond with Trump-style aggressive diplomacy (if that's what some people here are suggesting) would be make him less likely to make concessions to China.
It is more the case that it is an opportunity for the US to reset relations with China, after the turmoil that Trump created.