Well, Germany got gas, very reliably, from the USSR before Russia all the way back to the Cold War. Hickups only happened when Ukraine and Russia couldn't agree on transit fees. Hence Nordstream 2. If NS2 wouod already be live, Russia could also just turm of Ukraines gas. Now they can't without directly hitting one of their biggest markets.
In a sense, not certifying NS2 limits Russias options. Not that I am convinced someone in the Gean government, old or new, ever thought this through so.