In chapter 40 of 'Beginning After the End', it could be that the story begins to explore deeper themes. There might be more in - depth exploration of magic systems if there are any in the novel. The political situation in the fictional world might become more convoluted, leading to more intrigue and drama. Characters could start to question their beliefs and values more deeply as they are faced with new situations. It's also possible that we see the start of a new arc that ties in with the overall plot, such as a search for a lost artifact or the discovery of a hidden power.
The Beginning After the End manga has indeed finished. It provided a satisfying conclusion to the characters' arcs and the overall narrative. Maybe there'll be spin-offs or related projects in the future, but for now, the main story is complete.