For reference, my previous best time abusing Method-0 in 7.3.5 was 32.4 hours(as show in the old thread). A difference of just over 8 hours; which isn't all that bad, all things considered. And I believe I made several errors along the way, which could be cleaned up in future runs. I believe that that gap could be significantly closed by using a monk's bonus, but I hate playing monk...so...yeah. YMMV
As you continue to push through end-game content and you raise your reputations with various groups, you unlock more quests that send you to the opposing faction's continent where you generally try to mess with them, gather intel on their movements, and, of course, kill a whole bunch of them. These quest lines are fun, but generally pretty short and don't actually propel you through much of the three opposing zones.
It still will be but it takes up an Azerite armor slot. ST is not as important as AoE when leveling because you want to grab a pack of mobs, burst them down, loot and repeat. For DK specifically, Unholy is better in my opinion for leveling because it has a lot more aoe than Frost with epidemic. Unholy was my second fastest leveling time and I did it on a pre-made character with no leggos or consumables.
Edit 20 It’s been a week since this post and a lot of people are still reaching out to me with questions which is fine. I have had a few different people reach out to me to help make YouTube videos based off this guide and more info in BFA which I’m more than willing to do. Whoever gets the videos up first I will link them here for you guys to enjoy.