Firstly, you seem like a sweetheart, and a mature soul.
Secondly, if I were in your position, I would give myself enough time to really find peace about the fact that you're broken up, but not so much time that you start getting your hopes up again (because there is a teenny chance--like maybe 0.1% possibility--that if you meet up with her IRL and very calmly put the onus on her to explain (a) why she didn't communicate with you regarding the voluntary simplicity stuff (i) because you're not as hardcore as you might come off, which you would've shared if she had opened that topic up for communication and (ii) because she presumed that that was something you wouldn't be comfortable giving up to change to her lifestyle, which you say isn't incompatible with your preferences anyway.
Then I'd bring up (b), the mismatched feeling pace, in context of your past relationships, and just throw it out there that you're intentionally expressing your care for her because every woman deserves to be cared about, love is a verb mentality (stressing that you don't love her, because that would make her uncomfortable)--i.e. you're the kind of guy who learns from his experiences and makes an effort to grow. (GROW mentality is key with INxJs. Constantly growing and developing into a better person, or challenging yourself.)
Then, finally, I'd casually mention (c), your introversion, but instead of giving reasons for this one, just own up to it, throw your hands in the air so to speak, perhaps delve into MBTI for a moment and say how it was something, like point (b), that you would've made a concerted effort to meet her needs, if only she had communicated that to you.
If you keep a don't care at all mentality (the slightest care will be sniffed out and she wouldn't be interested) own up to your part, and put the onus on her to explain why she didn't communicate all those things instead of making assumptions, there's a teeny chance (like, really small, 0.1%) she might be interested. But of course she wouldn't say that, unless you got up and walked away (before talking everything COMPLETELY dry) and in parting said that if she ever changes her mind you would be interested in a relationship with her, but since that's how she feels you wish her all the best, and say that you're excited for your own life to see what happens next and where life's journey takes you.