I don’t want to sound like groupthink here, but definitely agree with the above posters. Haste should be part of your Destro PvP stat priority, right behind Mastery. Don’t stack 100% Mastery. I originally geared without much Haste and adding it really has been a QoL improvement in PvP.
For PvE...
Arcane and Fire relics drop from mobs in Suramar, but Suramar mobs don’t scale down to level 20-25. So farming usable Arcane and Fire relics (or any twink gear) off those mobs is impossible.
That’s why +7 Arcane/Fire aren’t listed in the farming spots. You’ll either need to farm legion...
An alternate Highmountain farming spot for ilvl 28 greens - Mightstone Flankers and Mightstone Slingers at 54, 63. Nice little spot just outside of Thunder Totem with a repair vendor close by.
Aslo, if you are looking for Legion Invasion farming for the +7 Fire Relic, the WQ in the northeast of...