This is such a hard book to summarise. My advice would be to experience Cutler for yourself. Find some radio clips on BBC Radio (via the BBC Sounds app) or use Spotify to find his work.
He has this comforting, yet uncanny quality to him. A cognitively dissonant Grandparent that occasionally addresses you, before returning to a strange unknowable mental realm of semiotic intricacy.
His work is surreal but on an intimate scale. I'm reminded of the world of Frank Key (of Resonance FM fame) who has a similar vibe and is another favourite of mine.
Maybe it is marmite, either you love it or you hate it, because I have shared him with other people but they tend not to respond to me about him.
Nothing about him is particularly unsettling or objectionable... maybe it is just confusing to people and that can be equally uncomfortable for some. The 'difficult to understand' often presents a barrier - in that the effort to think overwhelms people.
In reality, it is less about thinking - more about feeling. But that too, for some... well...