As a (very) slow reader myself, this is (very) encouraging from John Piper:
One Advantage of Reading Slowly
The fact that hundreds of the pages of God’s inspired word are devoted to poetry moves me. One of the effects is to make me aware that God thinks the sound of language matters.
God has blessed and humbled me with the inability to speed read. I read about the same speed that I talk. I hear what I read as I read it. For years I tried not to. Speed reading consultants (I took their courses—in vain.) say that pronouncing the words, even in your head, turns a rabbit reader into a turtle. No use. I’m a turtle.
So I take heart that so much of the Bible is poetry. It is self-evident to me that poetry is not meant to be speed-read, but ordinarily read aloud. So I would encourage you to supplement your speed with slow savoring of the way things are written to be heard.
Consider this observation about what happens when poetry is read aloud and read well by a person who understands it.
“Even after almost three millennia of written literature, poetry retains its appeal to the ear as well as to the eye; to hear a poem read aloud by someone who understands it, and who wishes to share that understanding with someone else, can be a crucial experience, instructing the silently reading eye ever thereafter to hear what it is seeing.” (John Hollander, Committed to Memory: 100 Best Poems to Memorize, 1)