It just gets… dumber? It’s pretty subjective though.
Spoiler alert- Creatures from other dimensions with mind control technology spanning entire spacetime cannot squash humanity because of a single human/protomolecule hybrid - Laconia’s absolute compliance with Duarte ruling is so mindless. No conspirators apart from a lone mad scientist… no one even tried to use protomolecule technology to take over the power. - Humanity adopted protomolecule technology and colonized hundreds of worlds all within lifetime of main characters. The power belongs to Laconian empire. But they still cannot get insurgents found and punished. There is a fucking asteroid base, and Laconians cannot find it.
Not a dumb part, but the main characters, being separated for a long time, don’t get their own interesting storylines. It seems like authors got bored with characters and didn’t know what to do with them. New characters are usually boring. Duarte’s daughter, Kamal’s son - they are just background… The only strong character in focus is Tanaka.