Armon's Storage House

Using the key needed for the spell, you conjure a large wooden double door in range that lasts for the duration. The doors leads to an extradimensional storage house and is 10 feet wide and 10 feet tall. You and any creature you designate when you cast the spell can enter the extradimensional space as long as the doors remains open. You can open or close them (no action required) if you are within 30 feet of them. While the doors are active, they are visible from the outside and onlookers can see inside the space if the doors are open.

Using the key to lock the doors when closed, closes the extradimensional space away until the key is used once more to reopen it. The space is linked to the physical key, and only the key used when casting the spell can summon and open that spells' extradimensional doors.  Using a new key and casting the spell opens a different extradimensional space, even if the key is identical to another key with a space. Once the spell is linked to a key, only a Magic action and the spell prepared is needed to open/lock the space. You do not need to recast the spell. DON'T LOSE THE KEY OR YOU LOSE YOUR STUFF!

Beyond the door is a storage room with an atmosphere that is clean, fresh, and dry.

You can create any floor plan you like for the storage room, but it can’t exceed 10 contiguous 10-foot Cubes. The place is furnished with shelves if you choose, but nothing else in the area. The shelves created by this spell dissipate into smoke if removed from it.

While the doors are open, fresh air moves in and out.  When the doors are closed for more than 1 minute or locked, any creatures or living objects left inside the extradimensional space are expelled into the unoccupied spaces nearest to the entrance. Likewise, If any creature inside Readies an Action all creatures and/or living objects inside the extradimensional space are expelled into the unoccupied spaces nearest to the entrance.  If you are more than 30 feet away from the entrance for more than 5 minutes, the doors automatically close and lock.  If you leave the key in the extradimensional space and the doors automatically lock, the key is left in an unoccupied spaces nearest to the entrance.

Should the Key ever get Destroyed

Hope is not lost.  You will need a new key worth 5 gp, as well as items that will be consumed by the new recast of the spell.  Consumed items need are: a gem-encrusted chest worth 100+ gp, a miniature door carved from ivory worth 5 gp, a piece of wood, and the feather from a Griffon.  The recast must be done as a Ritual and it will consume a third level spell slot. Place all items in the gem-encrusted chest and start the ritual.  At the end of the ritual, the new key will be able to access the destroyed key's extradimensional space.  If multiple keys are destroyed, this step is done for each individual key. You cannot combine the ritual process.

Note: this will only work if the key is destroyed.  If you lose that key....that's on you.