>>39334617Fire Emblem Three Houses is specifically made to be beginner-friendly. The Fates series (Birthright is easiest, Conquest has a better cast) and Awakening are also independent entries.
Animal Crossing New Horizons, like every other AC game, isn't dependent on its previous games so you can always start new. You can buy Animal Crossing New Leaf really cheaply now, or even download Pocket Camp for free on your phone right now if you have the space.
You can play Splatoon 2 without previously playing Splatoon, the single player campaign still makes sense and online play is based on player skill, where level and experience are only an indicator of how long someone has been playing the game.