Knowledge Only User is the recommended license for the specialists who will create and manage knowledge articles in Salesforce. Knowledge Only User is a user license that allows users to access and use Salesforce Knowledge, but not other standard Salesforce objects or features. Knowledge Only User is a cost-effective license for users who only need to work with knowledge articles. Verified References: :
https://help.salesforce.com/s/articleView?id=sf.users_license_types_available.htm&type=5 :
https://help.salesforce.com/s/articleView?id=sf.users_license_types_knowledge.htm&type=5