Let her go, she has made it pretty clear and any pursuit isn't worth the energy.
Forgive my bluntness, but it seems what you want is to simply get laid, get the poison out and all that. You've not tried Tinder or other equivalent apps?
Well, you definitely misread what I said, then. For one thing, I don't need Tinder because I can get laid easily these days. This may have been a struggle in the past, but it isn't anymore.
What I want was a serious relationship, but I wasn't feeling it with her despite a strong sexual tension that I'm going to hate myself for not seeing that part of it through, as I have been about every similar past relationship. Like the ones I didn't get and can't get now. I guess it's the challenge that is appealing on some subconscious level. Not getting what I can't have anymore leaves me wishing I'd done things differently.