Congratulations! Now you are the owner of a magic key, which, if inserted directly into the air, will open a door-portal to a pocket dimension. Both the door and the dimension are hidden, and nothing in the world can get any access there without your permission or even know they exist in the first place. The door is also covered by a perception filter, so only you can see or interact with it.
The key is tied to your soul and you can summon/unsummon it will. It cannot be stolen or lost. The inner space of the dimension is a small sea with a paradise island in the middle, on which stands your personal Sweet Home. Or is it a Mansion? No, wait, it's a Tower floating in the Clouds! And now it's a Cabin in the Forest with mountains in the background... Hmm, it seems that on your first visit, Sweet Home will take exactly the form that you find desirable for relaxation and living.
The house itself is clearly "smart", it can rearrange the rooms, change the interior and, of course, self-clean or even self-repair. The presence of ethereal servants is optional.
Inside the house there are already several pre-configured rooms: Your private quarters, where sleep is five times more effective than anywhere else. A kitchen equipped to prepare any meal and whose food stocks will be replenished every day. Control Center where you can customize how your home/dimension looks like, day/night cycle, weather and other things. And a small workshop where for now the only thing you can do is duplicate the key to create another portal door in a different location or combine several keys into one master key.
If you have any other house-type objects, you can put them inside your pocket dimension.
Important: any changes you want to make (add a room, increase a dimension, upgrade a workshop, etc.) will require energy. Absolutely any energy that you possess will do - mana, ki, psi, etc. If you are an unpowered person, you can use your stamina, but expect it to take much longer.