China “bailing out” Hong Kong is a common myth popularized by the CCP [0].
China refused to interfere with Hong Kong during the 1998 financial crisis, according to former Chief Executive Tung Chee-hwa [1].
The Monetary Authority head did not acknowledge any help from China back then [2].
[0] https://medium.com/@lineposthk/%E5%AF%92%E6%9F%8F-%E4%B8%AD%... (in Chinese)
[1] https://www.scmp.com/news/hong-kong/politics/article/2101761...
[2] https://hk.finance.yahoo.com/news/%E4%BB%BB%E5%BF%97%E5%89%9... (in Chinese)