Kenshi said:
First we have the revelation that Namekians were from another universe pretty much conflicting with Piccolo's blood recognizing the environment of Planet Namek as the ancestral homeland of his people (despite him born on Earth as a Mazoku clansman), as well as the fact that Namek exists in Universe 6 as well
To be fair, we've yet to see the kind of environment that U6 Namek has, making it plausible that the Namekians migrated between these twin universes after leaving the other dimension and Rou Dai Kaioshin being aware of them in the Boo Arc makes it apparent the Namekian race has existed for over 75 million years, more than enough time for the environment of Namek to be something all Namekians would be naturally accustomed to even if not their original home.
As for @SIAD's question on the scaling, I wouldn't say Vegeta should be any stronger than his Moro Arc self. Whis' statement doesn't really say much when the context was of fighters within U7 when Whis only questioned what might appear in the universe and bringing up people they already know such as Jiren or Broly would be redundant when Goku is questioning the existence of anyone he's not aware of, otherwise he wouldn't need to question there being others Whis knows who are stronger when Beerus had just stomped Vegeta. Until we get some more solid feats and statements, I wouldn't say Vegeta is currently a match for Jiren's full power.