[RPG] use Spell Mastery, Expert Divination, and Mind Spike to regain infinite 1st level slots


I was planning on making a divination wizard build in D&D 5e, but something dawned on me. Could I technically cast infinite level 1 spells, by choosing mind spike as a spell mastery and having Expert Divination?

Spell mastery: (Level 18) Choose a level 1 and Level 2 spell. I can cast this at the lowest level without expending a slot. This allows you to cast a level 1 spell and level 2 spells as many times as you want

This means I can just spam mind spike. But there's more. If you read Expert Divination:

Expert divination: When you use a level 2 or above divination spell, you regain a spell slot of a spell lower than that level

With mind spike being a Divination spell, it works with Expert Divination. It also does a 3d8 damage (though it does require concentration).

Couldn't I just spam mind spike, while continuously regaining first level spells?
I don't think I'll do this in the campaign because if this technically works, it is pretty broken, as I'll be able to spam a first level spell (like shield for example) or if I multiclass into Cleric, be able to spam cure wounds forever if I use mind spike each turn (which is crazy) or other spells using the first level spell slot. I want to know if this is possible, and I haven't been able to find a question / research based on this.

Best Answer

The feature descriptions you quote in the question do not match the officially printed versions, so I would double check that your source is legitimate.

The quotes and links below are taken from DNDBeyond, which is officially licensed by Wizards of the Coast to host digital versions of D&D 5e publications. These quotes match exactly the Player’s Handbook.

Expert Divination only works when you expend a spell slot.

Expert Divination (PHB, pg. 116) says:

When you cast a divination spell of 2nd level or higher using a spell slot, you regain one expended spell slot.

Spell Mastery (PHB, pg. 115) says:

You can cast those spells at their lowest level without expending a spell slot.

This means that casting one of your Spell Mastery spells without expending a spell slot will not trigger Expert Divination.

Note, these features have remained untouched by errata since their original printing.