Should I have known better or did I deserve this?

My ex (F26) broke up with me (M23) after a few months of our relationship deteriorating slowly. She named incompatibility, growing apart, and my lack of accountability and consistency as the reasons it wouldn’t work. Obviously I tried to fight for us but she made up her mind, saying we wouldn’t work now or in the future, and that we could maybe be friends just not now.

It was the worst feeling ever, she was so cold and I hardly recognized her anymore. I felt so guilty for letting it happen like this. We had become long distance and while we still went on trips, dates, got her flowers, gifts, and visits, I got worse at being emotionally intimate, vulnerable, became dismissive of her feelings to try and keep her happy. I see all the places I got in my own head and made it worse.

I unfollowed her immediately from socials so it wouldn’t hurt but I missed her. After a couple months I felt compelled to break no contact and apologize sincerely, stating how I wronged her and taking ownership of my actions. I heard nothing. I know she doesn’t owe me anything, but then my birthday came around and still nothing.

It’s now almost three months, she went public on her socials and I see her and her ex following each other. They had been on and off for years, toxic, immature, barely even a relationship. I remember her telling me we were the longest one she ever had (1 year) and that she never had done so many things before like even a Valentine’s Day. So to me it made no sense to insinuate this situation when he was blocked for being so bad of a man. It felt like a slap in the face.

Now I don’t know how to take this, if the breakup was a rouse for her to get back with the familiar. If I truly messed up and there’s no going back. I can’t help but think if I do all the things the ex did like being persistent and not letting her go that she would want me back. I feel used, shameful, guilty, jealous, angry, and deeply sad about how this happened that I’m not sure how I should take it. Any insight would help I’m just dumbfounded by this development. And what hurts is that I still love her so much and miss her deeply.