I thought this location was rumored and discussed before, but everything I could find was this: News on NO TIME TO DIE (no spoilers) 
Almost every article about it mentions that it looks like the entrance to a Bond villainâs lair. Spitsbergen is a rather emote location, they could have gone there, shoot some establishing exterior shots and no one would have noticed. And the interior shots completely at 007 Stage in PinewoodâŚ