Just make sure you don't downloaded anything on the setup Switch 2 account first. If you link your Nintendo Account to the initial Switch 2 user account, the former will override the latter.

Like the Nintendo Switch, the Nintendo Switch 2 allows for each console to hold multiple User Account Profiles (up to 8 total users can be created on a single console).

The Nintendo Switch lets players access their games and most saved files on multiple devices. Find out how you can play across multiple devices here.