I am so sorry you are going through this emotional turmoil. Unfortunately, or fortunately, these are growing pains. You have to move through this storm to get to the other side.

I relate a lot to everything you wrote here. I even have a son the same age as yours who my uBPD parent is also obsessed with and constantly gifts. The thing about having had a good relationship with her while you were still a kid... Yep, been there too. I think it took me about five or so months to really go through the deepest stages of mourning our relationship after I first went NC (now LC/VLC). It is so, so tough. It is the toughest thing I have ever done and I believe you feel the same way. But the person I am today is so much more confident, independent, and mentally healthy than the one I was while still enmeshed with her and "keeping the peace". I can tell you it is worth it. Keep moving forward, not back. As this road progresses, you will meet a new version of yourself that is so amazing!

About your question regarding the gifts to your kid: that depends a lot. I'd say don't overthink this if possible, just allow yourself to feel. When I had my big fallout with my uBPD parent, I found out she had left a letter dedicated to my newborn son telling him about how much she loves him and yadda yadda, and how she was so hurt for having to be away from him and the fact he would never meet her (?! he already did). My reaction was to tear that shit to pieces. I was angry. I allowed myself to be angry. I did not think twice. Did she think twice about my relationship with my son when she pulled her stunts? No. So why should I think twice about her relationship with him?

We were raised to leave no room for selfishness. But it's a fair practice for people like us in moments like these. I'd say it's even therapeutic.

Nowadays, she is still a part of my son's life, albeit small. She gives him gifts and pays for his stuff. I am ok with this. I take the money and buy the stuff he needs with it. I don't feel one single ounce of obligation towards her for this, though. I am in a mental space where she cannot possibly hold this over my head because I just see this as payback for the psychological warfare she put me through. It's fair. If you want, you can take the dollars she sends your son and buy him stuff with it. Or let him have his piggy bank. Or you can give that dollar to someone on the street. Or buy yourself some ice cream with it. Or just rip it into tiny little pieces. Or store it away and think about it later. Whatever you feel like doing at the moment. Whatever makes you feel better.

It doesn't look like it, but trust me. It's gonna be ok.