Someone Explain Cormac McCarthys Stella Maris to Me

I've been a huge fan of the late Cormac McCarthy for years. Have read and loved the majority of his work. But I have to confess I find 'Stella Marie' puzzling. 'The Passenger' was light on plot even by Cormac's standards but there were enough hooks to keep me interested. Stella Maris as far as I can tell (admittedly I'm only halfway through it) appears to be Cormac reflecting on his own fascination with physics. The main character Alicia comes across as overly evasive. Almost like an enigmatic try-hard.

If the answer is 'finish the book', so be it. Maybe all is revealed. But at present I'm at a complete loss as to this addendums appeal or even what it adds to its companion.