Per PTR notes, patch 12.0.7 will buff certain xp activities significantly. Projected to drop around June 17th.
Significantly increas[ing] the amount of experience earned from completing the following types of Midnight quests: 1st time delves (Delver’s Call), Midnight dungeon quests, Prey, and weekly Renown activities.
Myself, I have added void assaults, classic cooking/fishing dailies, and Normal Prey quests into my leveling routine.