>>ncr100+Rm
My understanding is that the normal rule here is that the launching state has jurisdiction over (and international legal responsibility for) what is done by a spacecraft, but I’d bet that if private parties crashing their spacecraft into those of other private parties with widespread, economically significant use became a thing, a whole lot of countries in which one or more of the companies have assets or interests would discover jurisdiction in underused provisions of their domestic law rather quickly, no matter where either of the craft involved were launched.