I believe it will be March 2025, therefore I voted for Jan-April 2025.
This is based on a lot of the reporting lately. Honestly, a March release worked wonders for Switch and I could see the same for Switch 2. 3D Mario in March, Mario Kart in April, Animal Crossing in June, Mario Party in September (40th anniversary of Super Mario Bros., so why not celebrate with a party?), Luigi's Mansion in October and Pokemon in November would all be huge. And then you could have the likes of Kirby, FE, Yoshi and SSB in 2026. Sprinkle in some Zelda remakes as well and then 2D Mario & Splatoon 4 by the end of 2027. First few years of Switch 2 could be bigger than Switch 1 honestly.
Everything I've mentioned for 2025 would definitely be due for new games by then. Looking at Switch 1 top sellers, all of those franchises exceeded (far exceeded in most cases) 10m sales.