Honestly pikmin 3 feels like a sequel to pikmin 4 more than the other way around IMHO. the multiplayer is superior in every way, the second screen is used in perfection with the split control system (GOOD DANDORI REQUIRES SUCH).
I think that 4 feels closer to 1 and 2 than it does to 3. I guess 3 has more of a focus on efficiency and problem solving compared to 4 which seems very combat focused?
Imo 3 feels different enough to be worth checking out, especially if you already have the game.