I'm not saying it would be a verbal and written requirement to participate, and yet, they might have to for other political reasons, like a supply of additional defensive equipment or maintenance programs. For instance, some countries did participate in wars on the side of NATO even though they are not even a part of the alliance. All at the expense of human lives and taxpayers' money [1][2].
Before you say that the US interventions are not NATO interventions, could you name at least one instance from this list [3] where the US was not an active participant of and was actually disapproving of other members' actions? I'm asking because there's a valid growing sentiment with an element of truth in it that NATO without the US is not a potent alliance.
[1] https://en.wikipedia.org/wiki/5th_Mechanized_Brigade_(Ukrain...
[2]https://en.wikipedia.org/wiki/6th_Mechanized_Brigade_(Ukrain...
Well, now you're arguing something entirely different - that NATO will rope you in without being a member. Hard to say it's a downside of joining if it happens anyways.
> if NATO gets into a conflict with China over Taiwan, there's a highly chance that Finland and Sweden would have to send their troops to fight and die there too
Nothing in NATO's organization or the Treaty itself supports that assertion; in fact, it explicitly says otherwise.
A similar scenario with Taiwan would not mean "Finland and Sweden would have to send their troops to fight and die there too" as you asserted; they'd have the option to join in if they saw fit.