The Taiwanese support for pro-independence actually skyrocketed in 2019. I don't think anything bad happening to Hong Kong activists would be a good look for China.
Yes in 2019, look what's happening to TW politics now, green fatigue, DPP anti PRC rhetoric secured a couple elections but now the island new gen is increasingly jaded and post political because they realize the DPP Anti PRC card isn't improving their QoL. VS a few years post getting crushed, HKers also post political who realized they can simply live much better lives by embracing mainland (SZ) and not be such nativist/supremecist. Reality is democratic and shitlib politics is structurally failling everywhere, if the authoritarian gives you a priveledged deal, many TWer might eventually take it. Just look at HK reaction to recent fire, HKers lamenting how much more SZ and mainland tier1s have their shit together. The vibe is changing. PRC needs carrot and stick for TW, like how it's always been. Let's be real, in a post TW crisis there will be winners and losers, TWers need to see how winners are treated (tier1 affordtable life style) and how losers are treated (Gaza). Nevermind DPP just banned XHS because they realize they're losing culture war to mainland.