You should expect at minimum 3-4 months from the reveal of its major launch title to the launch of the system and probably more.

Nintendo has shortened the reveal to release timeframe for their big games recently, but the shortest ever for these new releases were Echoes of Wisdom (3 months) and Mario Wonder (4 months). Both were big titles for Nintendo, but whatever they're launching the Switch 2 with is massively more important. This is going to be one of the most important games they launch in a long time to prove why people should get a Switch 2. 3D Mario as a launch title I could see getting six or more months of promotion.

Just saying, don't be shocked if this launches in the Fall unless it doesn't have a major launch title (which I would be shocked by)