Do magic items lose their magical durability in an Antimagic Field?

Question

The DMG says this about magic item durability:

Most magic items are objects of extraordinary craftsmanship. Thanks to a combination of careful crafting and magical reinforcement, a magic item is at least as durable as a nonmagical item of its kind. Most magic items, other than potions and scrolls, have resistance to all damage. Artifacts are practically indestructible, requiring extraordinary measures to destroy.

Antimagic field's interaction with magic items is defined as such:

The properties and powers of magic items are suppressed in the sphere. For example, a +1 long sword in the sphere functions as a nonmagical long sword.

So would an antimagic field suppress the damage resistance of magic items, allowing them to be destroyed more easily? If this is true, then destroying artifacts would be trivial with a high-level caster.

Answer 1

Regular Magic Items? Yes.

You've already provided the only relevant quote from Antimagic Field:

Magic Items. The properties and powers of magic items are suppressed in the sphere. For example, a +1 long sword in the sphere functions as a nonmagical long sword.

If you want to see high-level characters flee like scared children, break out an antimagic field alongside black puddings or rust monsters.

Artifacts? No.

You've skipped an earlier part of the spell description (emphasis added):

Spells and other magical effects, except those created by an artifact or a deity, are suppressed in the sphere and can't protrude into it.

Artifacts are created with techniques that are simply better than normal spells.

Answer 2

Artifacts are beyond normal mortal meddling. However, normal magic items lose everything.

The pertinent passage in the spell is (emphasis mine):

Within the sphere, spells can't be cast, summoned creatures disappear, and even magic items become mundane.

As for artifacts, same discription in the next paragraph:

Spells and other magical effects, except those created by an artifact or a deity, are suppressed in the sphere and can't protrude into it.

Deities pretty much ignore mortal magic (unless they choose otherwise for some unfathomable reason) and artifacts do pretty much the same.

and further in the description:

For example: a +1 longsword in the sphere functions as a nonmagical longsword.

Mundane meaning normal. This alone would indicate to me that no magic would exist to make the item any different than a typical longsword found at a castle forge other than possible decorative intracacy.

Artifacts have specific modes of destruction and mortals really don't have a loophole in that regard.

While back (in 3.0) my party ran into a dead magic zone and they had to fight rust monsters in it. 3 characters lost magical weapons that day.