All it says in Warband Collections tab in game is that it’s a boss drop. But after checking every Vault of the Incarnates boss loot table, it doesn’t show up. Are these still possible to obtain? I’m brand new to WoW, just started with The War Within so some of the older expansions requirements for gear is a tad confusing.
It looks like that are from the heroic version of vault of incarnates. It’s the first raid of the previous expac. If you make a post in trade chat in the weekend, you should be able to get a group going.
A lot of tier set off-pieces like this will be listed as boss drops but are only available by converting eligible gear in the catalyst on a specific class (demon hunter in this case). This will be the same for several TWW tier appearances so be sure to hoard some pieces to convert later if you have your sights on them.
You have two options:
Loot leather boots from heroic vault of the incarnates and convert them in the catalyst (it should be free). You can only run it once a week and will require a group.
Farm forbidden reach to purchase the leather boots with overflow, upgrade at the upgrade NPC with storm sigils from various sources on the forbidden reach, then use untapped forbidden knowledge to max out the upgrade path. Convert in the catalyst for heroic variant. Alternatively if you loot the primalist leather boot token, you only need to upgrade with knowledge, avoiding sigils.
Because you’re new, option one is most likely the easiest but will require a group to farm transmog there and is timegated. You can make or find a group to run in the legacy raids section in the group finder. The second option can be done solo and is less gated, but if you haven’t done dragonflight, will require completing campaigns to unlock the relevant zone and the currency system is a bit convoluted.
You can use the catalyst in dornogal to convert old gear, also.
Here are some item links for forbidden reach if you want to investigate these: