GUYS... just realized something: Pokemon Masters is clearly built in the current game engine they also use for Sword and Shield. The fact that every freakin' trainer from past gens is getting a fully fledged 3D model in Masters is a pretty solid indicator for a World Tournament in Sword/Shield, or something even bigger combined with a Battle Frontier (the huge Poke-London area on the Galar map always looked post-gamey to me).
We know GF don't really let their work go to waste (looking at you, Pokemon 3D sprites 2013-2019 and beyond...), so I don't think they put in all the work just for Masters.