I think you have given Morrison too much credit. Morrison's outburst of the tweet actually showed that he isn't a statesman. And Morrison's gesture isn't a sign of capitulation. Morrison has no plan to walk back from the changes that Australia has made. The downfall of Trump might have persuaded him to tone down the tension a bit but it is his constituents especially the business community that forced him to make small amends. But don't expect any meaningful changes from Australia. Due to the media and politicians that incited so much hate from the general public for so long, there is really a very narrow path that Morrison could walk.
Except iron ore, every exports from Australia are replaceable. Some of them such as tourism, education, wine, and coal could have permanent implications if China banned them for a long period of time. It is the looming threat of permanently losing its share of exports to China that frightened Morrison.
As for China, I don't know if you have noticed. Ever since Huawei has been banned 2 years ago. China has been patiently asking Australia to change its stand and warn Australia not to go down that path. Instead of adhering China's advice and warning, Australia refuted and called China a bully. It also doubled down on more restrictions toward Chinese companies and investment. After covid debacle and search of Chinese journalists, China finally has enough of Australia and fought back aggressively. I think China is under no illusion that the olive branch is just a tactic and have the determination to punish Australia til other countries understand China patient is not unlimited.