[RPG] What happens when you put a Portable Hole inside a Bag of Holding while on the Astral plane

From the DMG p.141:

Magic Item Resilience

... Most magic items, other than potions and scrolls, have resistance to all damage. Artifacts are practically indestructible, requiring extraordinary measures to destroy.

The Portable Hole isn't an artifact (q.v. DMG 219), so it only requires ordinary measures to destroy. It does take twice as long to destroy as a non-magical hole (hah!), but that's as far as the DMG takes us.

So any mutilation of your Portable Hole is going to go outside RAW, and you'll have to work with your DM to figure out if, how, and any consequences. (The effects you mention from Bag of Holding are certainly suggestive and may inform this discussion, but are not controlling.)

Advantages of the Bag of Holding:

• Removing items costs an Action, whereas with the hole you have to actually climb in to get something. Drawing an item from the bag in combat is reasonable (if expensive); from the hole, not so much

• The bag is less suspicious. Unless you draw something that obviously would not fit, a Bag of Holding just looks like a bag. A portable hole is going to look highly magical when in use.

• Needs less space. The bag is just the size of a bag; the Portable Hole requires a 6ft diameter space to open up against. Not very practical in the crowded space of a dungeon.

• Not as hard to get. The Bag of Holding is an Uncommon item, the Portable Hole is a Rare.