This should pretty much be the conflict in a nutshell.
We just don’t see it now because most corporations are focused on their profits for the next quarter and don’t seem particularly motivated by anything too far ahead in the future. With the vast resources of the galaxy within arms reach (due to advent of warp/jump tech), they would now be looking much further ahead into the future and the corporation with the most resources at their disposal will stand the greatest chance of survival…or even domination. Those that fall behind in that race will be at the mercy of those that gain the most resources.
It is, in a sense, the wild west of land grabs with stakes and outcomes that will play out many millennia in the future. Strategic seizures would also allow one corporation to dictate business to any other corporations that have to transit their territory. With corporate militarization, they have to consider how their logistical train can be destroyed as well.
There’s also the economy of such rapid expansion. Is it more economical to place refining, manufacturing, and construction elements in every place they occupy, or would it be better to create centralized mega-hubs with minimal levels of extraction and defense in adjacent systems (i.e. expand fast, leave minimal footprint, reinforce if threatened)
The corporations of the future are essentially nation states. Any actual government would either have to keep pace with these corporations by massing their own resources, or play those corporations off against each other to keep them weaker. If they didn’t, they would effectively become puppet states and meaningless…if they aren’t already.
You may think such things are unnecessary with such abundance, but it boils down to a Darwinian survival of the fittest. If even one corporation goes down that path of gluttony/dominace, then any other corporation/government would have to follow suit or risk their own demise.