Back at the start of the month, we found out that Amazon Japan had a listing for a Switch version of Ancestors Legacy. That was the first we heard of the quad-based, real-time strategy game making its way to Switch. While we haven't had confirmation from the dev/pub yet, we do have some more retailer evidence.
Both Amazon.com and retailer Deep Discount have added listings for the game as well. They both show the game as launching on May 19th, 2020, which is the same date listed on Amazon Japan. With the evidence piling up, it seems like this port is the real deal.