The opening is great. A nice mood is set.
I’d recommend making your 2nd act gradually more energized. Then consider a pause to riser / swell into your big 3rd act. The 3rd act and climax needs to be much bigger and should fully realize your original ideas from the beginning. Fully realizing your opening ideas is useful for trailer editors who might want to cut straight from the beginning to the end (and then maybe back to the opening material for the end of the trailer), and also is more satisfying to listen to for your fans.
You need a massive ending, even for a drama track. Think as big as you can get, then go even bigger at the end… this the standard feedback we get in the trailer world : )