Stopping pumping at 6 months?

First of all, I know that I can stop at any time. I think this post is for reassurance and some actual data if possible.

I am EP for my first baby. I am now almost 5 months PP and my goal was to stop pumping at 6 months. I was always an undersupplier and I've made peace with it. I make enough to give her 3-4 bottles of breastmilk a day. It was previously more, but I've cut down to 4-5 PPD now. Baby has taken wonderfully to formula and is doing well. I hope to introduce solids soon.

Now that I am approaching my goal, I am having mixed thoughts as I know is common. I've read so many posts on this sub about this exact thing. I keep worrying about if I am denying my baby immune benefits. There is also the aspect of my mental health. 4 PPD is very manageable for me. But I feel that my anxiety has been pretty bad postpartum. I don't think it's due to EP stress, but I don't know if breastfeeding itself worsens my mood. I also feel unhappy with my looks, and I hope to lose weight/diet once I have weaned. I also have a mild pelvic organ prolapse, and I wonder if that will improve as I wean too.

All in all, I am wondering if anyone has experience with the above when it comes to stopping breastfeeding. Did you feel that your mood and your body returned after stopping? Does anyone know of any genuine benefits of continuing to give some breastmilk for 1 year if I'm combo feeding?