I’d probably make getting the Legendary cloak and working on it the first priority.
Here’s what you need to do get the cloak.
(1) Unlock World quests. (Looks like this is done.)
(2) Unlock Naz’jatar. The quest “The Wolf’s Offensive” should pop up after you’ve unlocked world quests and leads to “Send the Fleet” which will start off the Naz’jatar quests. (It looks like you may have already started Naz’jatar.)
(3) Unlock Essences. Magni will show up in Naz’jatar with the quests for this shortly after you get to your faction base in Naz’jatar. Follow those quests until you’ve unlocked the forge and activated your first essence. (Again, it looks like you’ve done this as well.)
(4) Start up the Wrathion questline. The quest “An Unwelcome Advisor” should pop up once you’ve unlocked essences. (If not, try porting to Boralus or relogging to get it to pop.) This quest chain is pretty long, but it also acts as a tutorial for all of the 8.3 content. At the end you’ll get your legendary cloak.
You’re gear level is borderline for the 8.3 quest content. It’s probably doable, but you’ll need to be on your toes. You will get upgrades along the way which will help. If you feel like you’re stuggling, spend some time doing Naz’jatar stuff and run some heroics (which drop ilvl 415) for gear. Also, make sure to hit up the new world bosses after you’ve unlocked the 8.3 content which drop ilvl 445.
After you’ve got that going, if you want to work on pathfinder you’ll need to start up Mechagon. The starter quest for that opens up a bit into the Naz’jatar storyline. It has one world quest up per day, but it’s worth a decent chunk of rep. So, if you’re short on time, try to get that done, and worry about the other daily quests there if you have time.
For Naz’jatar rep, your big chunks are going to come from the story and Emissaries. The pet battles on Naz’jatar also offer a decent chunk of rep the first time you do them. (You’ll get a quest item the first time you defeat them that turns in for 250 rep.) The world quest doesn’t need to be up to fight them. (Mechagon has similar thing with it’s pet battles, but the quests only give 75 rep.)