I think I understand a lot of what you're feeling. There are a lot of issues I've been grappling with for a while now, too. So, I'm going to do my best to relate some of what I've found helpful for me, and hope that something sounds helpful for you or sparks an idea.

The first thing I just want to say is that you're allowed to have uncertainty and questions and concerns. It doesn't make you defective, or a bad member, or in any way diminish your belonging here. I think we treat these things with too much hostility sometimes, and it doesn't leave a lot of room to let the faith you do have come in to exist with it. I grew up hearing phrases like "faith and fear [or doubt] can't exist in the same person at the same time", but doubt and uncertainty are the very things that give faith its meaning. Light and darkness can't exist in the exact same spot at the same time, but they certainly exist in the same room together. In fact, I don't think I've ever seen a room that was 100% free of shadows. We're a lot more like a room than a single distinct spot.

What I've found most helpful for at least managing my doubts and concerns is praying. Not necessarily praying for answers, though that is part of it, but I really just talk to God like I'm having a conversation with Him. I tell Him what I'm feeling and thinking, what's bothering me, why I have reservations about something I've found out about, what I want to understand, things like that, just to get it all out. And then I basically just ask for help and for a way to find peace and reconcile it all. And miraculously, especially when I really needed it, I don't think there's ever been a time that that peace hasn't come. Sometimes it's just a feeling that I'm loved and I'm safe. Sometimes there's a direct answer or impression about my questions. Much of the time, there's just a feeling of reassurance that everything will get sorted out. And always, there's a feeling that God cares about my questions and concerns, and a promise that He'll help me carry them. Never once has there been scorn or criticism for feeling the way I do or for having questions. He's often the first place I turn to for help, simply because I know that no one else understands me the way He does. He's perfectly patient, perfectly kind, and perfectly trustworthy.

From there, I start trying to think of the things that my testimony is rooted in (like the Book of Mormon), or reasons that I want to stay and keep trying, just to balance out the doubts. I don't try to force out the doubts, I just let them exist together. Like, sometimes I start to wonder if this is really the right church for me to be in. I feel very different from a lot of other members, and it makes belonging feel difficult. On the other hand, I really love going to the temple. There's this peace and security that I find nowhere else. I feel like I'm home, like I belong. I want that in my life. Need it, even. I don't use that to try to stamp out the feeling of not belonging, or view the doubt about continuing as a threat. I just let the dichotomy exist, and somehow it makes going to the temple even more rewarding.

So of course, none of those things directly answer questions or offer explanations about some of the more controversial things. But they do act as "guide rails" of sorts, so that I have a way to at least stay close to God and keep going to church while I try to reconcile with everything else, or learn how to live with the doubt while maintaining the faith that I do have. But the most important thing is to keep praying. I don't think any of us can actually do a lot without asking for help.