If God is power beyond this reality, is there an infinite measurement of possibilities? Is there an infinite scale of beauty, goodness, joy and love that is God's power? Or do these have a fixed 'highest capacity' that God has/IS?

Put it this way, nothing is 'wetter' than water...that is 'wetness'at its highest value but milk choclate has sweeter alternatives.
The classical definition of this would suggest that the difference between God's beauty, goodness, joy, etc., is not merely in quantity or degree but in kind. That is to say, God's goodness is a different kind of goodness to that enjoyed by humans.

This is a common theme throughout patristic and Western scholastic thought, but perhaps the most influential theologian is Pseudo-Dionysius the Areopagite (Denys to his friends). He talked about these attributes in his work On the Divine Names with the word "hyper" attached to them. "Hyper" means "over" in Greek, so God's goodness is hyper-goodness, "over-goodness" or "beyond-goodness". God is not good in the way that we know goodness to be, but in a way that is above and beyond it. Moreover, it is also a kind of pre-goodness, that is to say that God's goodness is in some way causative of the goodness that we know.

There's a decent introductory summary to these ideas in the Stanford Encyclopedia of Philosophy.

A similar (and indeed indirectly derived) way of thinking is that of Thomas Aquinas, whose theology remains enormously influential in the Roman Catholic Church. According to Thomas, when we speak about God we speak in terms of analogy. That is to say, when we say "God is good", we mean it in an analogical sense. It does not mean exactly the same thing, and it doesn't mean something entirely different. There is a relation, but the word is not simply transferrable from the creature to the creation. Again, there are ideas of causality inherent to this.

This is unfolded in question 13 of the first part of the Summa Theologica.

So, again, the classical answer to your question would be that the kind of goodness/sweetness/beauty attributable to  God is to some degree a different kind of goodness/sweetness/beauty to that which we comprehend in our mortal embodied lives.