So the issue is: who represents China? The government in Beijing or the government in Taipei?
Later, Britain signed the Sino–British Joint Declaration of 1984 with Beijing to decide the (then) future of Hong Kong. If the Sino–British Joint Declaration is revoked, things could be different.
Just recently US is asking the Beijing government to repay the debt of Qing dynasty [1], which Beijing said would be the responsibility of Taiwan. Following this logic, receiving Hong Kong from Britain could also be the responsibility of Taiwan.
[1]: https://www.bloomberg.com/news/articles/2019-08-29/trump-s-n...
Since 2001! There's a century of this debt getting rolled over to greater fools.
Having said that one must note Taiwan has a law in the pipeline (1st reading) to give up The claim of mainland. You may be surprise Of communist china Actual objection To it But not HKER or Taiwanese. In any case Even if they keep the claim This path is Only valid In theory but frankly not in Practice.
Personally i will continue our fight. Taiwan has enough of their own problems. If they can free from mainland, That is great already.