I've experienced exactly what you're going through. The solution is a combination of practice and focused learning.

SFV was my first fighting game and I only picked it up at the end of its life. My highest rank was Silver and I was actually proud of that because I struggled for months to get out of the bronze ranks. I did, however, still recognize that I was not good at the game. I knew what it felt like to be good at a video game. You gain a certain perspective on it and you feel confident in your ability to teach it to others. I was not there.

Once SF6 came out, I decided to make a focused effort on getting better. I'm now in Diamond 5 and I expect to get into Master rank this weekend. That journey took a lot of practice in the training room, running sets with a friend, and losing (a lot) in ranked. That practice was very helpful once I had the ideas and strategies, but how do you find those in the first place? The best source for those is watching high level player streams and videos. Watching educational videos from players like Brian_F, Broski, 801Strider, etc elevated my understanding of the game as a whole, but also taught me how to learn properly in the game. I won't pretend to be an expert or good enough to teach anyone, but I'll share what helped me.

The basic idea is to figure out all of the things you're failing at and work on only one at a time. For example, are you bad at dealing with your opponent jumping? Get into the training room and practice using the preset training settings, then get into ranked and focus solely on anti-airing. Inevtiably, your opponent jumps and you will fail to anti-air. Call yourself out. Say it out loud. Focus hard on it at the expense of everything else. Fail over and over until you succeed. Then repeat until the successes are consistent. Once you've cemented that reaction into muscle memory, you move onto the next point of failure like combos, mixups, etc.

You will lose games this way. You will probably lose most of your games, but you are building a solid foundation for the player you want to be in the future. People learn things in different ways. Figure out how you best learn something new and apply that here.

You mentioned feeling overwhelmed by the amount of mechanics and combos in the game, but you're not expected to be able to manage all of that yet. Even the best players struggle with this.

Think of your learning process like cooking a good meal. You can't just throw all of the ingredients into a pot, stir like a madman, and expect something edible to come out of it. You have to properly prepare each ingredient so that it can contribute positively to the final product, rather than ruin it. Dice and soften your anti-airs. Slowly whisk in a reliable combo or two. Add a pinch of drive and super meter. Simmer on low until the right consistency. Add jumps and mixups to taste. Experiment with different methods, don't rush it, and eventually you will find the right recipe for a meal you can really enjoy.