What is the difference between the groups Users and Domain Users?

Users is a built-in local group that exists on every machine; Domain Users is a global group in AD that contains every user account of the domain.

• Domain Users lives in Active Directory. Every user account created in the domain is automatically a member. It is the same group on every machine.
• Users is a built-in group on each computer (on a domain controller, the domain's Builtin\Users). By default it contains Domain Users, but also Authenticated Users and INTERACTIVE, so it can include accounts from trusted domains and local accounts.

So Users is the broader of the two. Replacing Users with Domain Users on a folder narrows access to "every account of our domain". With IGDLA you would go further and grant access only to a domain local group for that specific resource.

Go deeper:

• Microsoft Learn: Domain Users and Users — the two groups side by side, including that joining a domain adds Domain Users to Users.