It sounds like you've got a few things going on here, so I'm going to try to give you a few bits of advice that hopefully cover most of what you're asking.
- Lack of confidence
You say your prose sounds clunky, boring and doesn't capture the moment. Perhaps this is true, perhaps it isn't. I would highly recommend joining some kind of writing group. My preference is to find an 'in-person' one, where you actually meet face to face to give critique on each others work. You can often find these on the meetup website, some of them have their own websites, or you could ask at your local library.
The benefit of this will be manyfold. You will get genuine feedback about your writing (not friends and family who just tell you it's great) and genuine advice on how to improve. You will see what level your peers are at, and get a sense on whether your writing is working for readers or not. Hopefully, it will give you more confidence in your writing.
I realise that getting solitary writers to go out and share their work with strangers is a big ask, but if you can do it it will be worth a hundred books.
Or, if you really don't wan tto go outside, you can try an online critique group, such as https://www.scribophile.com/
- Building tension
Annoyingly, my experience is that 90% of the thousands of books about writing out there all deal with the same high level stuff (such as overall structure, how to build a character, how to avoid using adverbs), and it's quite difficult to find good books that actually deal with the nitty gritty of things like how to build tension, how to reveal salient details, how to drip feed a character's backstory - in the kind of practical, detailed way that I would like to see. So sadly, I don't recommend a book for that.
(If anyone out there does know of good books which do offer more practical detailed advice for already experienced writers, please say in the comments!)
My general advice is:
Use a time countdown. Build tension by having a strict deadline by which something terrible is going to happen, and refer to the time going down in increasingly short intervals to increase the tension more and more. You can see an example of this here: https://www.fabulaargentea.com/index.php/article/pray-on-the-weak-by-katja-l-kaine/
Analyse a real life example Find a scene in a book that you found really tense, photocopy out the pages and annotate it to death. Pay attention to what the author did to build tension, notice what techniques they use. Then try to emulate (not copy) that.
Show the tension through the physical If a character is about to reveal something important and potentially destructive, how do they feel about it inside? Try to suck the reader into the physical sensation of anxiety and nerves.
The action reaction cycle Finally, I find the action reaction cycle a useful way to ensure a scene has pace and naturally grips the reader. You can read about that here (disclosure, this is my site): https://www.novel-software.com/blog?article=the-action-reaction-cycle
I hope some of that is helpful!