Magic pervades the D&D setting, like atoms and photons pervade reallife.
In this context, the terms "mundane" and "supernatural" become meaningless.
More meaningful terms are "ordinary" versus "extraordinary".
The rule of thumb is, if something is ordinary in reallife, then it is also ordinary in the D&D setting.
If something is extraordinary in reallife, highly unusual, remarkable powerful, or impossible, then it is also extraordinary in the D&D setting.
With this rule of thumb in mind, within the D&D setting, it is also possible to talk about "ordinary magic" versus "extraordinary magic". Magical phenomena that are impossible yet comparable to things that happen in reallife count as ordinary. Eberron gives a sense of what this looks like. Settings that magically mimic reallife, like an animated book that moreorless resembles a tv screen, or a weapon that resembles a fiery explosion, are within the realm of ordinary.
How much magic and the genres of magic vary from region to region, but all of it is within the scale of ordinary magic.
The Common levels 1 thru 4 and Uncommon levels 5 thru 8 represent the ordinary experiences within the D&D setting.
Any higher tier − Rare levels 9 thru 12, Very Rare levels 13 thru 16, and Unique beings of levels 17 thru 20 − are Rare and rarer. Most people in the D&D setting never encounter this magnitude of magic during their lifetimes.