Before reading Witness for the Dead, I took the excuse to reread Goblin Emperor for the nth time, and oh wow is it still such a comfort read for me.
I think it's really that Maia is an endearing (and easy to connect to for me) character. An anxious, apologetic, people-pleasing half-goblin forced into being an emperor that he doesn't know anything about. Wanting to be kind and make friends but struggling with being awkward and trying to do that through an extreme power dynamic differential.
It takes a little to get into the swing of the various courtiers and naming conventions, but it feels a little like a reflection how lost Maia is himself.
Overall, it's just a nice gentle character arc of growing into competency and friendship that always seems to be exactly what I need.