Astral Version: astral-1.4.2
Patchouli Version: Patchouli-1.15.2-1.2-34
Forge Version: 1.15.2-forge-31.2.8

The player can blow up the walls of the inner realm and venture outside.
I've tested this with TNT, TNT minecarts, and end crystals, as the player can get those in their inner realm in survival by using an offering brazier.

Update: Beds can also be used to blow it up. Even though beds cannot be offered directly, by offering leaves, dirt, bonemeal, and string the player can acquire the things necessary to create a bed in the inner realm instead.