It is no good pretending that Braga Santos continued to compose the sort of rich, romantic, lyrical music of the first four symphonies. These are wonderful, life-enhancing works which a number of us love unreservedly. They were written when Braga Santos was in his twenties.
But Braga Santos evolved his idiom as he got older and came into more contact with contemporary music. His music did become more dissonant and (as you say) acerbic.His later music may therefore come in some ways as "a disappointment" but that is clearly the music he wanted to write and the listener needs to come to terms with that and take it on its merits
The vocal ending to the sixth symphony excepted, I am not enthusiastic about the later style of Braga Santos. It appears that in the new CD, which comprises 8 premiere recordings, all the music - apart from the
Piano Concerto - belongs to the early lyrical phase of Braga Santos. Whilst it seems certain the music will fall short of the quality of the lyrical symphonies, the CD, nonetheless, is an interesting prospect.
The sleeve notes make interesting reading:
https://www.naxos.com/mainsite/blurbs_reviews.asp?item_code=8.573903&catNum=573903&filetype=About%20this%20Recording&language=English#