Well, that citation is fanmade and not official. It makes it sound like the Sturgian culture sprang out of initiative by the in-game Nords, which is not the case. The role of the Nords in the foundation of the Sturgian principality is as mercenaries, mirroring the use of norse mercenaries in the foundation of Kievan Rus, which the faction is inspired of.
That citation isn't really claiming anything, its as vague as the devblogs are. Its not like the lore of this game is particularly fleshed out and well established. It was just a link to show the earlier poster that I was replying to no, Sturgians are not a pure Danish/Norweigan inspired faction. That's it.
If you read the official devblog, its not like TW has some master world building narrative, they're just trying to appease people by making a fun gameplay faction and then post-hoc justify it. None of this fleshes out in gameplay, its not like you recruit Nordic mercs & Russian villagers, its pretty vague backstory. The lore is inconsistent from Warband to Bannerlord for obvious gameplay reasons. To be frank, one can reasonably speculate, the only reason the Sturgians are Nordic influenced at all is because people would throw a hissy fit if they couldn't emulate vikings.