Yes of course motion prevents collapse in a system about the center of gravity so long as the object is outside of the event horizon.
The term 'event horizon' typically refers to a black hole scenario which wouldn't apply to our solar system example. It would be more correct to say that motion (kinetic energy) prevents collapse in a system that is devoid of friction or other outside forces.
In a pure vacuum universe with just two mass objects in motion, they might orbit a common center of mass indefinitely. If we add plasma in there or generate friction in some way, they may *eventually* merge, but that could take eons depending on the circumstances.
That works obviously for any portion, *sub*part of the Universe, as distinct from the Universe as a whole. It doesn't work (not so far as I understand) for the Universe as a whole,
I think we better talk about your assumption that the universe is somehow different as a whole compared to it's parts. In an infinite and eternal universe, how and why would it be different? Even in a finite universe that rotates around a common center of mass, why would it be different? It's not different when we go from a solar system to a galaxy, nor when we go from a single galaxy to a galaxy cluster or size things up to a supercluster, so why would it not apply to *any and all* systems in motion?
except in the obvious way of expansion that continues, or attenuates to asymptotic, or eventually becomes contraction.
I'll grant you that without any other possible influences that a static universe (in motion of course) might *eventually* (eons) tend to collapse due to friction. If however you add even a *tiny* amount of current and light and neutrino kinetic energy from suns and such, how can you be sure it would *ever* collapse?
Admittedly an expanding or contracting universe would be inclined to continue to expand or contract, but I have no evidence to suggest that it *must* collapse, or *must* expand based strictly on GR theory. Einstein's entire point of adding a non-zero constant to GR is so that it *is* compatible with a static universe scenario.
His non zero constant might be caused by just about anything, from light emissions from stars adding kinetic energy to the system, to neutrino emissions from stars, to EM fields, to just about anything. GR theory is not incompatible with a static universe, and objects in motion will continue to be in motion indefinitely without any external influences.
I'm still thinking on whether current flows can over long time allow some equilibrium, countering gravity, in your notion of a static Universe.
I would say that it adds filaments and "structure' to a universe in motion, and it has an influence on pinching things together, and it influences the motion of plasma.
I'm inclined to believe that we live inside of an infinite and eternal universe that has always existed and which has a 'structure', just like our bodies have "structure'. Gravity and motion could easily be the two things that mostly keep it "in balance", but EM fields have a very definite influence on the movement and behaviors of plasma.
Inside our solar system that takes the form of auroras, electrical discharges in planetary atmospheres, the sun's corona, the discharges in the solar atmosphere, the solar wind, polar jets, etc, etc, etc. We can *see* it's influence on plasma in the lab. It must also influence the behaviors of plasma in space too.
Not so sure that can work, actually, but still thinking over it, and don't know if it will take hours or days or months, lol.

Take your time. I've been mulling over various cosmology theories for many decades.

It's a fun lifetime hobby. Don't rush it.
One early question that happens right off is how are the currents just the right amount. More likely they'd be a different amount -- either too much, causing accelerating expansion, or too little, merely participating with gravity as a jr. partner.
I'd say it depends on the circumstances and the conditions of the plasma. For instance gravity seems to be the dominant player in terms of planetary motion in our solar system, but EM fields seem to dominate in the areas I mentioned earlier, in terms of the solar corona, solar wind, CME's, aurora, etc. Some events in plasma are heavily influenced by the circuit energy of the whole circuit, and gravity has only a minor influence on the motion of that particular plasma. A solar flare for instance can release particles that strike the Earth at 1/3rd of the speed of light. Gravity certainly had little or no effect on those particles in the flare event. It might have slowed them down a tiny bit, but the EM kinetic energy of the flare event had a much larger effect.
I'd say that's true throughout spacetime. Some types of motions are dictated mostly by gravity, whereas the motion of some plasma is virtually unrelated to gravity. It depends on the specific conditions of the plasma.