I just reinstalled after 8 years and leveled a monk to 60 in 9.2
I’m just confused on how I should best utilize the leather working. Considering the new zm gear and items, can someone give me some advice for a MW monk PvE? I feel like I’m going to make leather working investments and then find out later that it was a complete waste.
Others can speak to this with more authority…
My choice, if I were in your shoes, would be to skip crafting entirely. To go double gather and sell your stuff on the AH and just buy what you need. Or, if you choose to craft, I would go Alchemy/Herbalism. Flasks and Potions are useful, plus you get extended times on your Flasks.
There isn’t a lot of margin in crafting and selling in the AH. Even to get usable gear for yourself, or Legendary blanks, you are literally going to go through astronomical amounts of mats before you get anything worth equipping or selling. The gold you spend on leveling would be better spent just buying what you need.
That’s just my opinion. I quit leveling crafting stuff in WoD for the most part. I do have an Alchemist to do Flasks/Potions and a Tailor for bags. That is pretty much it. I don’t play either regularly. The Alchemist made it to 60, the tailor is still level 51. Neither has a Legendary.
Also… Welcome back! 
Edit - I see you are on Silvermoon. So you are linked to my realm. The guild Absolute (Hydraxis) would be worth looking into. Lots of new players there along with some returnees. Some having come back after being gone since WoTLK. My most active character is in that guild.
I considered doing a straight gathering guy but i did that with previous toons so i wanted to try something new. Clearly not the best strategy jumping into an expansion this late. If i changed professions do i lose my leatherworking level if i decide to go back to it? Im not sure how things work these days. Lots has changed.
Oh nice ill have to take a look. Im not even sure how guilds work anymore. How would i look into Hydraxis these days?
Drak’thul, Skywall, Silvermoon, Hydraxis, Borean-Tundra, and Mok’nathal are all joined servers. So guilds can pick up folks from any of those servers.