The best selling 2D Zelda is currently the Switch version of Links Awakening. Just realized, that game released five years ago.
An original new game should be able to pull better numbers than a remake when released on the same hardware but my gut tells me that it will not catch up.
The last original 2D Zelda was Tri Force Heroes and that game was a bit of a letdown and did not even break 1.5 million units sold, roughly one third of the sales of a Link Between worlds. Being an original game in the Zelda series does not guarantee sales. Echoes of wisdom needs good reviews to hold up.