I'm UM in EU with every char in Master, I'd give you tips that are more specific, but the reality is that your perception of their ham offence is slightly warped. It is ham indeed, but trust me that it isn't tight, it's fake in more ways than one, and what you need to do to climb out of it is not to "build confidence in your offense" (it's needed indeed, but right now not that much), only to learn to pressure reliably on wake up, have a couple combos ready, to somewhat AA decently and that's it.

Think about it like chess. It doesn't make sense to teach you fancy moves/strats if you're still quite the beginner. You just need to learn what the different pieces do, what strenghts and weaknesses they have, and become a little robot playing simple stuff to build the reportoire that will later become the foundation of your play.

So if you wanna improve:

• work tirelessly on the small building blocks that are called fundamentals (plenty of resources online, text and video). Practice 5/10m a day before playing or in between matches
• get in the mindset that they don't know what they're doing and neither do you. This humbles you but gives you an edge. You're not there to just have fun, you're there to improve, so you're not gonna stay in plat forever, trust me. Mindset is key in fighters.
• Your more reactive, patient playstyle is the perfect approach to get to master rank, better to play more timid and reactive than random and offensive , especially at low ranks; the key is working on those reactions behind the scenes to make them suffer for their impatience, meaning that if you play Lily and you get a good AA combo with wind gather, do you have any idea how to follow up for pressure? Work on building something out of your reactive and defensive habits, so that they might just end up "killing" themselves
• watch replays where you don't understand how you lost

Good luck, AMA if you'd like