Splatoon 3 was announced in February and released in September (2021), meaning it'd be a 2026 release and AFAICT Splatoon has been a fairly big title so I don't think they'll have its announcement to release window straddle the holiday season

after the spin-off (which i would not consider 4) announcement, i think they'll focus on just this for the year

I would love to have more splatoon but they might be scrambling to do a new animal crossing. It's been over 4 years since New Horizons