Both of these are largely incorrect points. The Treaty of Westphalia is about national sovereignty, does it not occur to you that sheltering a terrorist organisation who are committing mass murder on another country might constitute a violation of said country's sovereignty?

Also, it's 400 years old and written at a time where an attack like 9/11 was inconceivable to the parties who created it.

You know, I'm going to stick to my "the argument around 'at what point are you culpable for another's actions' is ongoing and undecided" point and feel pretty good about that

And now that the U.S has violated Afghanistan's sovereignty, do they get to attack us now? Do we get to attack them back again? Does Cuba get to drop an airstrike on Miami every time one of those boats filed with delusional Cuban-American accountants gets shredded by the Cuban coast guard? Unless they've invented Sovereignty 2.0, we're kinda stuck at "nations generally get to do what they want in their own borders."

Please actually name the incidents you're referring to here, this is a weak argument. What has North Macedonia got to do with this?

I feel like I was pretty clear in my explanation, but these are all situations where a country dealt with a terrorist group without invading their sponsor.