It's not on the webstore or anything like that yet.
After its delay last week we MAY have a new target date for the Advance Wars reboot.
Listings on the on-device eShops in both the United States and Canada have the remakes coming out on April 8, 2022. It was originally slated for release on December 3.
Nintendo has not officially confirmed the new date, though we have requested comment.
UPDATE 6:05pm ET: Nintendo has responded to our request as follows: “Advance Wars 1+2: Re-Boot Camp will be available in Spring 2022. More information will be revealed in the future.”