Although the Super Mario Galaxy games aren't getting bespoke Switch 2 versions, they appear to be getting the next best thing.

First spotted by Vooks, various regional Nintendo websites have listed information indicating that the October 2 releases will have a patch on Switch 2 to enable mouse controls and 4k docked/1080p handheld resolution. The mouse information and October 2 patch date comes from Nintendo's Japanese language page for games with free updates (found here) and the resolution is quoted on both the North American and UK pages (NA version here).

The changes to Galaxy 1 specifically appear to be exclusive to the release and would not be included in a patch for the 2020 limited release of Super Mario 3D All-Stars (which notably did not include Galaxy 2).