Back to Detective Pikachu. So, both the 2 games and the film appear to place themselves in the anime continuity, though they obviously cannot happen in the same timeline (else we have two Harry Goodmans who were involved in a car crash, both had a son named Tim Goodman, etc., though the game one would happen earlier as Ash's Pikachu appears and the movie one would happen later, 20 years after the first movie). It's not impossible that similar events happened twice, but unlikely, even though the outcome differs. Yes, you could just say that the 2 games are in their separate self-contained universe, but that's boring. So, could either the film or the two games take place in the game timeline instead of the anime timeline? As mentioned, both seem to take place in the anime continuity. Pokémon say their names instead of growling (well, the film has a mix, but the game has a clear anime voice), Ash's Pikachu appears in the first game, a Jigglypuff very reminiscent of the anime appears in the film (though potentially not the exact same if Jigglypuffs don't live that long, have to look that up, the film takes place 20 years after the Mewtwo flees Kanto after all), and creator comments about the film imply a connection to the anime, though they are kept very vague. So, if anything, either both happen in the Anime timeline, or the film happens in the mainline game timeline (well, in one of them). I don't think the Detective Pikachu games can happen in the mainline game universes, just doesn't feel right. And the movie has a little fewer ties to the anime than the games, but I dunno. The Mewtwo backstory seems to align more with the film rather than the games...
Sorry if that reads a bit clumsy or if I overlooked anything, it's just a middle of the night thought without any research, still would appreciate your thoughts.
(Sorry, Mewtu is the german spelling of Mewtwo, fixed it)