This was was a short-book-length or very-long-short-story which I read online a long time ago, possibly self-published by the author.
There were characters trying out new inventions, but each time they discovered a new technology, the laws of physics changed to rule it out. This was due to a fight between some hyperdimensional beings, who turned our pocket universe into a prison, with the outside beings modifying the laws of physics as needed to prevent the prisoner escaping.
I believe the story opened with some characters who worked at an observatory, possibly named Chet/Chell?
This story may involve characters travelling to space, and returning hundreds of years later due to relativistic aging, only to find Earth devastated by a war. Only info-matics still works, with people learning to transfer consciousness to another body, but unable to do basic medicine anymore. This may be another story getting confused in my mind however.
Eventually, the guardian of the prison becomes incarnate in our universe, and fights it out with the prisoner. Chet is angry our universe is suffering due to this fight, and triggers the ultimate weapon, a device that forces the outside prison guardians to collapse the universe entirely.