Levels are more critical than gear rarity. If you keep doing focus sessions, any gear will quickly outmatch your current equipment.
Mystic Cabin is not worth it until you are in the end game as it gets quite expensive.
Time Rift is a great way to get loot regardless of your level as the fights are adjusted to your own level. Dying in the Rift is not uncommon.
Even though the raid has been only running for 1 season now, I can say that it’s the best way to get legendary glyphs.
Legendary Skill books are the best with a couple of special exceptions. Do not overinvest in non-legendary skill books as these can get quite expensive and Dream Dust is hard to come by.
There are different builds out there, but without PvP, it’s hard to test how good they actually are.
Choosing Knight or Mage doesn’t really make much difference for you, but as there are MANY knights out there, choosing Mage could make yourself more valuable to combo with other players in the raid with the help of class-specific skill books.
There are 10 different glyphs and up to 4 pages with 5 glyphs each. You can put 2 glyphs of the same rarity in there. Keep in mind that legendary and divine glyphs have 2 different rarities.
Example: “Speed Glyph IX” and “Speed Glyph VIII”, both with divine rarity.
This is all I can give without investing a crapload of time at the moment and not spoiling too much for you.
I thought about writing guides (which I have for certain topics) but stopped due to it simply not being necessary. The game is easy to progress if you focus every day during work/school/whatever you do. So writing more extensive guides was never a thing.
If you have more questions, feel free to reply.