Can you use two wands to cast one spell?

Question

Basically, in the May 2019 Artificer UA (Unearthed Arcana: the Artificer Returns), the Artificer got two mutually-exclusive ways to enhance a non-magical wand to improve the spells it casts: the Wand Prototype level 6 class feature of the Artillerist subclass (which lets you add your Int bonus to damage for one cantrip), and the Enhanced Wand Infusion, which grants you a +1 bonus to spell attack rolls.

Is it possible to “dual wield” wands so that you can benefit from both of these bonuses at the same time?

Answer 1

These features should be compatible, though there is some awkward wording

The first important thing to note is that the Enhanced Wand infusion doesn't require you to actually use the wand to do anything, it requires only that you are holding the wand when you cast a spell:

While holding this wand, a creature gains a +1 bonus to spell attack rolls.

It's basically a prototype version of the wand of the war mage which has the same wording:

While holding this wand, you gain a bonus to spell attack rolls determined by the wand’s rarity.

You don't need to use the wand as a focus or actually involve it in the spell in any way. Though one imagines that is the narrative intent, the rules only require that it's in your hand when you cast a spell. Wands generally being one-handed tools, you are free to hold something else in your other hand, such as another wand, and use that normally too.

You will need to keep in mind that you need a free hand to manipulate material components and/or provide somatic components for spells, though; specific wands might or might not count as an arcane focus depending on your DM's ruling, which could obviate the problem for spells with inexpensive and unconsumed components, but for spells with significant material components - or spells with somatic but not material components - you can't get around needing a free hand.

The Artillerist's Wand Prototype feature basically lets you create a magic wand that only you can use which you can use to cast a cantrip. As explored in this question, casting spells from magic items is in most respects the same as having cast the spell yourself - you get the benefits of class features and abilities that interact with spells you cast, and you should also get the benefits of magic items like the wand of the war mage.

The only issue I can see is that the Wand Prototype description doesn't actually state that you cast the spell using the wand, it says that:

As an action, you can cause the magic wand to produce the cantrip, using your spellcasting ability modifier

But, keeping in mind that the Artificer is still UA material, I think this is an unintentionally awkward wording and using the wand prototype is not supposed to be different than casting a spell from a normal wand in such a manner; it should still count as you casting the spell for such purposes, and get the benefit of a wand of the war mage (or an Enhanced Wand made by infusion) if you happen to be holding one in your other hand.

Answer 2

As written, they do not combine/stack

You can definitely wield two wands, but because of the way the Wand Prototype is written, the +1 effect of an enhanced wand (or wand of the war mage) would not apply.

It's possible that because it's UA they didn't vet the language enough and ended up with a weird wording, but it's also possible that they purposefully made it restrictive. As written, it is straightfoward to me that you do not get the +1 benefit because you are not casting the spell; the wand is.

Some magic items allow the user to cast the spell from the item. The spell is cast at the lowest possible level, doesn't expend any of the user's spell slots, and requires no components unless the item's description says otherwise. (DMG, p. 141)

For the same reason, you do not gain the advantages of the Spell Sniper or Elemental Adept feats when using the Wand Prototype feature.

Jeremy Crawford tweeted an answer to a similar question with regard to casting a spell through an item:

If a magic item's description says you cast a spell from it, you can use Metamagic on the spell.

It is my understanding that this tweet is addressing items which say "you cast."

All of the DMG wands I was able to quickly search have phrasing that is some variation of: "you can use an action to expend 1 or more of its Charges to cast..."

The wording of Wand Prototype reads: "As an action, you can cause the magic wand to produce the cantrip, using your spellcasting ability modifier."

If Wand Prototype were meant to function like all other wands, it should read: "you can use an action to cast the cantrip invested in this wand with this feature" or something along those lines.

Currently, the Wand Prototype feature reads (emphasis mine):

Whenever you finish a long rest and your woodcarver’s tools are with you, you can touch a nonmagical, wooden wand and turn it into a magic item. When you do so, you invest it with one artificer cantrip of your choice—even one you don’t know—that has a casting time of 1 action. As an action, you can cause the magic wand to produce the cantrip, using your spellcasting ability modifier (other creatures are unable to use the wand’s magic). The wand loses this magic when you finish your next long rest.

Any damage roll you make for a cantrip in the wand gains a bonus equal to your Intelligence modifier (minimum of +1).

Specific to Carcer's comment:

I think this is an unintentionally awkward wording and using the wand prototype is not supposed to be different than casting a spell from a normal wand in such a manner;

I'm unaware of any DMG or book wand that utilizes a spell attack. The rest call for saving throws or are magic missile. I don't think there's precedent to say that it should be assumed that the UA writers just made a mistake.