That’s the reason most books can’t be adapted exactly as written. Unless the writing is so horribly stilted (X went to Y, X said Z to α, X had β happen to him because of α…) that you wouldn’t want to read it in the first place, you’ll need a large amount of narration and/or characters speaking their thoughts out loud, which doesn’t work most of the time and gets worse if they’re doing it solely for the purpose of the viewer getting into their headspace.
That’s the reason most books can’t be adapted exactly as written. Unless the writing is so horribly stilted (X went to Y, X said Z to α, X had β happen to him because of α…) that you wouldn’t want to read it in the first place, you’ll need a large amount of narration and/or characters speaking their thoughts out loud, which doesn’t work most of the time and gets worse if they’re doing it solely for the purpose of the viewer getting into their headspace.