OneGod means exactly what it says. It is One numerically and not qualitatively. God is One person, not three.
Of Whom speaks to the fact that this OneGod is the inspiration for all things, the seed of all things, the Father of all things.
By Whom speaks to the fact that this OneGod created all things by speaking them into existence.
One LordJesusChrist identifies this OneGod, giving the name by which He should be addressed.
We by Him tells us that we are born into this OneGod by virtue of what He, our LordJesusChrist, did in His suffering, death, resurrection and the gift of His HolySpirit.
The inspiration and power to create all things is the Holy SpiritOfChrist Jesus. The Word which spoke all things into existence is the LordJesusChrist.
Chapter 8 speaks mainly to the issue of eating things offered to idols. But in 1Cor 8:4-6 it more specifically comes against polytheism and the fragmentation of faith in the TrueAndLivingGod who is our LordJesusChrist.
Trinitarians deny polytheism but they also deny the single person of the OneGod.
The problem with multiple persons is the fragmentation of our focus.
Our faith must be focused in order for it to be effective. Satan injected a god of multiple persons into Christianity to undermine the power of pure faith InChrist Jesus alone.
Preincarnate Jesus spoke these words through Moses to all of us: You shall have no other gods before me. Exo 20:3