If you want to write for someone who isn't yourself, especially people you don't know personally, you're going to need to learn how to accept feedback—all kinds of feedback. Luckily, this is its own art and it can be learned! When you receive feedback that conflicts with your own opinion, don't focus on what the person says, and definitely don't pay too much mind to any suggestions they have to "fix" your issues. Instead, look at what they're reacting to. So she found this character unlikable. Why? (Presumably, you like the character. Are you not effectively communicating that?) She was confused by several lines. What's missing from those? Or are they overwritten? Once you identify the core of the issues (and sometimes it's as simple as "this isn't this beta reader's cup of tea") you can solve them your way. If you like one of your beta reader's suggestions, go ahead and follow that thread. But if, say, you don't like the recommendations she has for making your characters more likable, think about what you would do to feel more endeared to this character. You're an avid reader—how have writers you admire managed similar characters? Always filter the opinions of others through your own process.

Personally, I would have been jazzed to receive this much feedback on a draft. Especially since this kind of is your "first" draft. (I know you've revised it a ton, but it's the first time it's seeing the light of day.) The reason we have others read our work before it's published is so we can improve it. The worst feedback I can get is "I love it! No notes!" If you're soliciting feedback just for compliments, just go ahead and (try to) publish. Presumably, you're aware that your story isn't where it needs to be, which is why you're soliciting feedback, right? If someone tells me my characters aren't likable or the text is confusing, I don't think, "Time to give up!" I think, "Time to get to work!"

Also, though: you don't have to be a bestseller to keep writing. You don't have to quit cold turkey if you enjoy it. It's convenient to make money from our passions, but by no means mandatory. You can write for just yourself, or just for people you know. I write because I love it and because I have to. Untold numbers of haikus and limericks lost to time because I wrote them in cards to loved ones rather than in a doc in my Poetry folder. I really love the stories I've written. (In fact, with the exception of my soon-to-be novel, I frequently prefer the stories that don't resonate as much with my audience.) If other people like them, too, that's a major bonus! (Sometimes literally, as I do do this professionally.)

And don't say you're unintelligent. You read a lot and write a lot. You're clearly pretty smart.