For the Spear, craft Tempest Replicas, and force either Corrupted Bane or Fortifying Perforate, if you can accept the 20 Str/10 Dex Split.
For replica, your unweighted odds of each are 18.06% for Vicious, 8.36% for Fortifying Perforate and 8.28% for Corrupted Bane. With 1/6 odds of legendary, you’ll theoretically hit your 3 perk 1 in 398 tries if you lock Corrupted Bane. Slightly worse odds if you lock FP, and significantly worse odds if you lock Vicious, which you should absolutely not do.
For normal spear, your unweighted odds of each are 15.59% for Vicious, 2.38% for Fortifying Perforate and 1.71% for Corrupted Bane. So 1/1617 odds to hit your 3 perk Legendary.
With Bow, you can also use the Replica. You would need to force Penetrating Rapid Shot.
For replica Bow, your unweighted odds of each are 27.14% for Vicious and 8.14% for Corrupted Bane. So you theoretically hit your 3 perks 1 in 272 tries
For normal Bow, your unweighted odds of each are 13.95% for Vicious, and 1.69% for Corrupted Bane. So you’ll hit your 3 perks 1 in 2545 tries.
So you can see you’re significantly more likely to hit your desired item using replicas. However, they are BoP, so you can’t sell any of the missed items. Although there isn’t a huge market for PvE spears, anyway. And the Corrupted Heart Spear takes Asmodeum instead of Glittering Ebony, but should also salvage to Asmodeum.
I did my PvE crafting using replicas, and I made a Rogue, Corrupted Bane, Shirking Arcane spear. Was hoping for Keenly Empowered instead of Shirking, but it’s still plenty good. Obviously it doesn’t work great in a pure dex build, but there are spears like Javelin of Dryadic Empowerment for pairing as offhand with Bow as main. But for things like Depths, where I’m running Spear/Great Axe, it lets me get to 50 STR without having to put any points into it.