Similar Works to Schnittke’s Choir Concerto?

Alfred Schnittke’s Choir Concerto (1984-85) is seriously one of the most beautiful and nuanced choral works I have ever heard, and also one of the most unique to my ear; I have never heard anything like that, but that doesn’t mean that there’s nothing else like it, right?
What are some other choral works that capture a similar feel and similar sublime harmonies?
I haven’t listened to much of Schnittke outside of his choir concerto so I’m open to suggestions of his other works, as well as works by other composers.