I don't see this possibility as any less impactful. It all falls under the same rubric. In the end we will still be symbiotically connect to this greater being, either psycho-socially, cybernetically via the integration of our civilizations' systems with it, or techno-organicaly as you've described. The point is that life will begin to evolve entirely around its existence to the point where the future of history will in a sense belong to it and not to us as humans any longer (at least not i the way we think of history now). This will cause human philosophy to shift dramatically, especially if a post scarcity condition is also achieved. It will be a moment of utter existential crisis on a species wide scale that far surpasses our current anxiety about climate change.

In fact, that anxiety is of a similar kind but a far less directly acute or intense character (humans creating a system/systemic change more powerful than them which they can't figure out how to control). Same with nuclear weapons as well. These are systemic existential threats in the physical sense, but this will be one directly related to the concept of our own consciousness.

The possibility of full transhuman integration as a solution or outcome of the advent of AGI of course comes with the fundamental question of transhumanism: at what point does transhuman integration move us beyond the logical boundaries of being human? Is a transhuman a human any longer or is it some new species defined by being merely the organic extension of the AGI system? In either case, we're looking at a post-human future and the transition period into it will have a lot of features found in human culture today, namely a sort of religious conflict over the new AGI which will inevitably be seen as a God.