>>58852223GameFreak did not "take an extra year", they were forced to delay the game's release because of the Switch 2's delay since it was meant to be an early bundle enticer for those who weren't convinced by Mario Kart.
The leaked build from the Teraleak is 99% identical to Version 1.0 at LZA's official launch. As soon as they believed LZA was good to go, they sat it down to shift gears towards developing Mega Dimension, Winds & Waves, Winds & Waves DLC and Legends: Galar.