An unlikely winner here are countries sanctioned from latest semiconductor technology. Sooner or later China will be make chips that more than good enough for supercomputers. I know there have been Chinese designs in the Top 500 before.
Concrete example, a Saudi Arabian university has a supercomputer https://www.top500.org/system/178515/ this supercomputer is restricted to Iranian students. Otherwise Saudi Arabia wouldn’t have been allowed to have it. Now think of all the possibilities if we could tell the US to pounce sand.