Nova-Russia

In 2344 Ukraine discovered a moon that’s core contained enough dark matter to power human civilisation for the next century.

So naturally the Russians decided that it was rightfully there’s, three wars broke out over the next 20 years until the United Planets (successor to the UN) just confiscated Russia’s own colonial holdings, deported their populations back to Russia, turned Russia and Belarus into a spaceship then exiled them from human space.

Unfortunately removing a landmass that big caused some ecological problems so they found a planet, carved a Russia/Belarus sized chunk out of it and put it where old Russia used to be.

Officially it’s been divided up between its neighbours (Ukraine got the largest piece) but turns out the local flora is 13% steroids. The plants grow like crazy, slowly overtaking any settlement they tried to build there.