> a simple DMCA takedown notice

DMCA takedown has no legal basis outside the US. And it's funny you bring that up: the only reason why this has any relevance at all is because of the established norm for countries to sacrifice some of their sovereignty in exchange for being allowed to trade with the US. Now, with the US breaking trade norms and agreements, those countries can (and eventually will) stop complying, because they have nothing to gain (and everything to lose) promoting hostile foreign competition.