Leveling Quest Exploit Shadowlands (Patreon)

Get the Kyrian quest,

 An Inspired Moral Inventory - kill forsworn ascended. 

You are given the spear "introspection"  to kill elite foresworn ascendants. 

The spear trivializes the killing of the ascendants by removing their elite status. Killing 3 awards more than a typical quest and takes only a minute.

The quest can be dropped and repeated. Alternatively you can group your main  character with another character (including a free starter edition account character) and convert the group to a raid-this will stop all quest progress and let you use the spear indefinitely. 

Competition may be an issue. There may be issues with leveling to 60 prematurely without completing all the Shadowlands zones. Doing this with ilvl 123 gear I found this more efficient than questing, for raiders this should be very efficient, for players with ilvl100 (catch-up gear) this is probably not viable.

Edit: This seems to work best off-peak, with too much competition causing problems for some patreons. Patreon Bake below in the comments suggests a medium pop is actually better because they pull the smaller xp-inefficient mobs off you-I had no issue with these ,but I'm playing fire mage which is very efficient for aoe.