Do I need to assign a permission set to every Dropbox user?
Yes. Every user who works with the integration needs either Dropbox Standard or Dropbox Admin. Without one of them, the Dropbox File Manager will not work for that user, regardless of their profile, even System Administrator.
For most users that means Dropbox Standard, which covers all day-to-day file work. Reserve Dropbox Admin for the small number of people who manage workspaces, billing, and other users' connections. The permission set can be assigned from Setup, the user record, or through a permission set group, the same as any other.
Assigning a permission set does not consume a seat. Seats are counted from the number of users who have connected a Dropbox account, not from permission set assignments, so you can safely assign Dropbox Standard broadly. See the billing page for how seats and tiers work.
Note: A permission set is also not the same as a package licence. If a user has a permission set but sees a licence message, their Salesforce user needs the package licence assigned, which is managed separately under Installed Packages.
