Bring only the attributes that you need into Okta. For example, if you have a t-shirt size attribute in Active Directory (AD), but you don't need the attribute in Okta or in any of your applications, don't import the attribute into the user profile. You can add more attributes later as you need them.
Removing attribute mappings is more difficult. If you remove attribute mapping, Okta retains previously imported data. To remove attribute data in Okta, you need to intentionally map a blank value to the attribute in the user profile.