For mainstream Christianity the ultimate reality is described in abstract, physics-like terms (especially in the assumed/ attributed nature of God - the omni qualities, God's absolute unity (monotheism); creation from nothing, existing outside of time and space etc).
Consequently, the core Christian value of Love is also understood abstractly - and it is not at the heart of reality, it is not the first thing. For many mainstream Christians; these abstract attributes of God are far
more important than anything else: e.g. that there is one God, and that he is of total power, that God is qualitatively infinitely different-from and greater-than Men... these is in practice are more important than God being a loving God.
This has often been a problem for mainstream Christianity - where it has proved very difficult to hold Love at the centre of Christian belief and life; and where officially-recognised heresies have often been at the level of abstract and 'physics-like' metaphysics - e.g. the bitter and vicious Christology disputes of the second century AD onwards (i.e. how Christ is both God and Man), the disputes of the nature and relations of the Trinity (i.e. how Christ is God yet there is only one God), disputes over the possibility of free will/ agency (i.e. how that can be genuine agency in a reality with a totally known past, present and future) etc.
In general; the abstract metaphysical principles are accepted, and other things have to give-way to them (including common sense and normal logic - as with the standard definitions of the nature of Christ and the Trinity).
Mormonism assumes a biological, indeed human, ultimate reality. The primary reality is heavenly parents (who love and marry eternally), and primordial intelligences (divided between male and female), in a chaotic universe.
Creation involves God/ our heavenly parents organising the chaos, and procreating the primordial intelligences into sons and daughters of God.
At bottom, therefore, there is sexual differentiation (men and women) and human relationships.
Consequently (for Mormon metaphysics) Love is the 'first thing' in creation and in sustaining reality; i.e. the primary event in organising creation was the love of Heavenly parents; and their love for their children.
And this divine love is continuous-with/ qualitatively the same kind of
human love as we know among men and women, parents and children, at the
best moments of mortal life on earth.
Mormon metaphysics is that Love is the basis and reason for creation: meaning love between actual persons - not a physics-like abstraction.
Drawing this out as *explicit* metaphysics was something done considerably after Joseph Smith's death, by various intellectuals (Sterling McMurrin especially, but earlier BH Roberts) - but the substance was revealeed by JS and embodied in the doctrines of the church.