The quest you found in your abandoned quest terminal, the Essence of Anguish, is your next Shadowkeep campaign step. You need to grab that quest, and complete the cleansing of that essence, as part of the campaign. If you wish to view a campaign walkthrough, to help gain your bearings on the various steps of the Shadowkeep campaign; here is the link to a solid guide: https://www.shacknews.com/article/114274/destiny-2-shadowkeep-campaign-walkthrough