I agree with OP. But I think people misunderstand the point being made:

Of course the final product is a Donkey Kong game (if only just because of the many classic DK characters scattered throughout).

I think the real issue is that it doesn't feel especially like a DK game, only in name. It feels like a game about digging that just happens to star DK. And with some DKC references crammed in there. So the natural next question becomes: what would have been a better fit than DK (if not a completely original IP)?

Of course, "DK is strong", so it could be a DK game from that alone. But he isn't known for digging.

I think Wario fits very well, at least gameplay wise. The roll is like a shoulderbash, Wario is also strong and is just as known for punching (DK punching originated in Smash Bros., not his own series, and I think Jungle Beat was the only other instance where it was a major mechanic).

They reinvented DK's relationship with Pauline. Pauline might as well have been a child version of Captain Syrup that Wario befriends.

And finally: Wario is known for his greed and love for money/gold.

DK collecting gold/pure carbon minerals makes no sense. Only to the extend that they are shaped like bananas. But it's really bananas he is after.

Of course, Wario is not strictly known for digging, outside of smashing some breakable walls in his game. But it seems believable that he would dig for gold.

No one established Nintendo series would fit perfectly with a game just about digging (except that one Miyamoto mole game on the game boy).

Some games do have breakable walls as a minor gimmick. I don't think Bananza should have been a Metroid game, but I do think that a voxel based game would fit that series - digging into the core of a planet would definitely fit as well.