You can farm Mythics, though at that iLvL you might have trouble even getting an invite to a M0.
Personally I’d say farm out conquest. Every 500 conquest you start getting 415 gear, and after you progress through the caps you eventually get to 430 iLvL gear. Not the quickest way, certaintly, but the easiest for farm out for sure.
Join battle for nazjatar every 3 hours. Get supply drops once a day in Nazjatar for 75 conquest and 50 in Kul Tiras or Zuldazar. Seeing as you are Alliance, do the weekly quest Against Over Whelming odds for 50 conquest and a free 415 peice, CTA: (Mechagon or Nazjatar) and CTA: (Kul Tiras or Zuldazar) for 75 and 50 conquest respectively. There is a quest in Korrack’s for 150 conquest of which you have to kill Drek’thar. Depending on how much time you have to play you can burn out a conquest bar every 1-2 days for guaranteed loot.
Depending on your classes BiS Azerite traits and stat priority you can farm pristine manapearls in Nazjatar and upgrade benthic gear. Just buy the 395 ones until you get ones with the right stats and gems for the non-azerite pieces.