I did not. Maybe you can explain how is your statement, to wit: "However, the full number and types of dimensions (spatial, temporal, etc.) is both unknown and unknowable" not indicative that all that we can know is destined to end in speculation.
We are just observers. And just like a fly doesn't know he is actually rocketing through space at more than 550,000 miles per hour, there are many things we do not know and there are many things that we cannot know and some things we cannot know that we do not or cannot know.
A person pursuing certainty of knowledge via "hyperbolical/metaphysical doubt" might retrace Descartes' steps arriving at his conclusions, cogito ergo sum and God IS, though Descartes of course used different words.
God's Name is I AM.