After migrating from Knowledge to Lightning Knowledge, Authors need to have access to the record types associated with the article types they want to create. Granting Authors access to the FAQ record type will allow them to create FAQ articles in Lightning Knowledge. Verified References: : https://help.salesforce.com
/s/articleView?id=sf.knowledge_lightning_migration.htm&type=5 : https://help.salesforce.com/s/articleView?
id=sf.knowledge_lightning_migration_record_types.htm&type=5