How do multiple castings of Demiplane interact with one another?

Question

So for the spell Demiplane, it states:

Each time you cast this spell, you can create a new demiplane, or have the shadowy door connect to a demiplane you created with a previous casting of this spell.

Does this mean that you can, for example, create demiplane 1, then on the next casting, create demiplane 2, then demiplane 3, and then on a fourth casting, open demiplane 1 again?

If this is the case, does this mean that you can essentially have as many demiplanes as you want, each for a separate reason?

Answer 1

Yes, you can create an unlimited number.

As you already quoted,

you can create a new demiplane, or have the shadowy door connect to a demiplane you created with a previous casting of this spell.

It doesn't specify a limit of demiplanes you can have at a time, so you can have an unlimited number of demiplanes, each for their own reason.

Answer 2

You can have multiples, and get to any of them

The line you quote says

Each time you cast this spell, you can create a new demiplane, or have the shadowy door connect to a demiplane you created with a previous casting of this spell.

I have emphasised where it says a demiplane. If you could only create one it would say the demiplane.