Does the 3rd benefit of the (UA) Fizban's Platinum Shield spell stack with Evasion, so that the character only takes 1/4 damage on a failed Dex save?

Question

The new UA, Unearthed Arcana: Draconic Options, introduces a 6th-level spell called Fizban's platinum shield that can be cast on a creature within 60 feet of the caster, granting them a few benefits. The description of the final benefit reads as follows:

• If the creature is subjected to an effect that allows it to make a Dexterity saving throw to take only half damage, the creature instead takes no damage if it succeeds on the saving throw, and only half damage if it fails.

This has the same effect as the Evasion feature of a Monk or Rogue (or Hunter ranger, maybe).

Since this spell benefit and Evasion have the same effect but different names from different sources, would they stack with each other?
For instance, in the case of a 7th-level monk failing a Dex save against the fireball spell while under the effect of this spell, would they take a quarter damage?

Answer 1

No, you still only take half damage on a failed save

The problem is that the both the Fizban's platinum shield spell and the Evasion feature state that you take "half damage"; they don't state that you halve the damage. Whether you have either or both abilities, the damage you take on a failed save is changed from the full amount to half the full amount.