Your third act should be your new second act
I think the perc programming in the third act is pretty decent, and the string part is cool. That's your strongest aspect in this track. If you then went on and topped it with something even bigger you'd be in good shape.
That would the core of a salable track, I think.
What I'm not hearing yet is, a catchy progression or melody that I can remember when I step away from the track. Hazarding a guess that you intend the solo female vox to have that role, but it didn't really make a strong impression me the first few times I listened. That's what is making act 1 feel too ambient & "not saying anything". Act 3 is great for the reasons I mentioned but
at present it's also anticlimactic/overdramatic because there's all this dramatic accompaniment in a supportive role but it's not supporting something suitably epic (horns in unison blasting!).
The progression made me think of a motif from Man Of Steel (E C B G over Emin, E C B G over Cmaj, etc etc.). See if you can come up with something that sounds similarly "Monolithic" and iconic. If you have a melody that repeats the same way, or nearly the same way, over the two chords, it will feel like it's 'saying something.' Especially try playing around
B,
D# and
F# as these notes have radically different implications over the two chords. You can really build up a "fateful" or "foreboding" feeling, which seems to support what you're doing in the strings. The D# especially can feel really ominous since it creates so much tension in C maj.
Really famous track by John Murphy is a good example of this -