Square Enix has delisted Dragon Quest 11: Echoes of an Elusive Age from various digital storefronts to coincide with the launch of the new S version.
A notice on the Steam page for Dragon Quest 11: Echoes of an Elusive Age - Digital Edition of Light reveals the game was unlisted on Valve's platform "at the request of the publisher" - and will not appear in search.
The notice says Dragon Quest 11: Echoes of an Elusive Age, which came out September 2018, is no longer available, and points to the new Dragon Quest 11 S: Echoes of an Elusive Age - Definitive Edition, which came out 3rd December 2020.