I’d say the difference is that those territories were more or less “at peace”. The colonists had “won” the war, at least per some definition of winning.

Afghanistan was a barely held together mess even before we withdrew.

I’m not arguing one way or the other for Taiwan—I don’t want to go to war with China for all sorts of obvious reasons—but we would have the backing of the Taiwanese people, and that’s a major difference versus Afghanistan.