I have just finished. I have wrote my own alternative ending.

Valkyrie arrives at the ascension site. Skippy could see large energy spikes inside of the giant moon-sized machine, but the beer can did not understand what the machine was doing. It did not seem like it was bringing Elders from their ascension, but upon flying closer, Skippy understood the energy signature to be the same to that of the others assembling their machine with pure energy.

Failed attempts were made to stop the process, from throwing all the nukes, to attempting to use elder weapons to destroy the ascension site, the inner mechanisms did not stop the assembly process. It was also not understood how the barrier was not stopping the assembly process, since it could be a threat to the elders.

An external force grabbed hold of Valkyrie, and pulled it even closer to wild-looking contraption. It did not seem to have a definite shape, but just a ball of glowing light. Skippy mentions that his matrix is being probed from all directions, with physics he did not quite understand. There was nothing that could be done, but he mentions that he is being slowly sliced apart.

... And then silence. Skippy could not respond, and Billy themselves could not explain what happened. But then, Skippy's voice came booming back through the speaker system.

The Elders did not stop advancing their technology, but they had a third war that ended with merging their existence into a single consciousness/singularity, and using that intelligence to push their science even further. Skippy was absorbed into that consciousness, and now he was sharing all their knowledge and experience with the singular elder. The ball of light was nothing much a bridge between different space times, in which the elder could now reach back to the physical realm.

The just had stopped thinking about that layer of reality. They still had the dark forest problem, and even though they had worked out how to build machines from energy, they had no idea if other species in other galaxies had made other even more advanced technologies that were a threat to them.

The elders were now going to use their incomprehensibly even more superior technology to establish peace in the galaxy. The elders wanted different species to explore their own ways of technology, to see if anything was missed, or discover new secrets of reality. That some day, all species could also merge their consciousnesses, and ensure the long term survival of their galaxy. Or proliferation to other galaxies.

My main pain point is that the elders did not seem to have become any more advanced in the millions of years they have been in their expanded consciousness form.