We pretty much agree on the basic working principle of magic then.

I'd like to know where magic comes from and how it can be used... (with nothing or using catalyst like magical wand or other stuff) I like having both, magical wands are used to store magical spells in DnD.

It exist in the nature and flow naturally in the world.
It is generated naturally.
It could come from the stars. From it's light/heating or the particles emitted. That mean that some place would have more magic than others. Unless the magical nodes serves as high or low pressures zones used in the flow of energy.
Magic could come from another world through these nodes.

These are just ideas for discussion.