Looking for help ending this piece (based on a book I'm writing)!

Okay making this post is a pretty impulsive decision and I hope I'm not intruding, I discovered this place today. In summary: I'm 15 years old, and I've been trying my hand at composing for around a year and a half now. I've written a handful of pieces I'm proud of, mostly for string orchestra. I'm a former violin player turned french horn, but I would consider myself having a much better understanding of strings than wind instruments (when it comes to composing). In my free time I'm also writing a book that is currently in the revision stages, and the plot of that inspired my newest piece. This is my first time truly writing for a full(er) symphony ensemble (there are missing parts right now, like tuba, that may never get added because I tend to write for sound, not playability, though if anyone has tips for that please please send them my way!!) and I'm trying to really develop my style and just improve my composing overall.

Right now I am struggling with not exactly how to end this piece, but more of how to get there. It starts with mostly percussion to set the vibe, followed by an explosive entrance of the rest of the ensemble (0:57), then a softer melody (1:49) (there's more but I'm listing this for context). To end the piece, I intend to write just cellos playing that softer melody introduced earlier (in a different key I believe) with the recurring chimes over the top and probably other various percussion sprinkled in there (with attention on just the cellos). The melody will end and the piece will conclude like it started, with just percussion and a final chime hit. However, I have no clue what to do to get there.

The attached recording ends with a callback to that earlier melody, but from there I've tried probably five different versions, none of which I like. My goal was to write one final "heroic" melody with a minor twinge to achieve the proper mood effect, but I ended up adding brass over the last string part at 4:39, so maybe that could be the height of the piece instead? I do really like that part.

If anyone has any thoughts, any comments on anything in the piece, tips for compositional work, structural work, anything at all really, please let me know! It can be as long or as short as you like, I just would like help. I've never posted my music online before, know barebones music theory at best, and have a horrible ear for this kind of thing. Thank you in advance!!