I didnt have any birth injury or experience like yours after the birth. But I do experience spd symptoms from before I pee on a stick, so I can only comment on how to improve your experience durung pregnancy. I know that not the question you asked, but I know from experience that it can be better with careful management.
You don't say if you are already, but you need to be strict about spd protocols, from the moment you find out you're pregnant, ideally, but def from right now.
Start a specific spd program ASAP. I did one that was 20 mins of various exercises on a ball every night until 14 weeks, then started a pregnancy pilates course with a women's health physio. You can do these online.
If you are extremely strict, you can have a better experience. It sounds like your experience was very severe last time and exacerbated by the badly managed delivery, but you should be able to avoid that extreme.
Things I followed religiously on my 2nd and 3rd pregnancy (and made a massive difference) :
-No walking. Walking is not good for unstable hips. I would literally only walk from door to car - pretend you're a celeb in sky-high heels!
-No sitting with my hips lower than my knees (no soft sofas)
-No crossing my legs
-No heels.
-no hoovering, mopping or pushing a trolley. Nothing that involves shifting weight and leading with one hip
-avoid picking up other children, and never hold on your hip. I would bend down to my toddler's level and have them sit on my knee for cuddles.
-No throwing yourself into bed - sit on the side, then swing legs in. Same for turning in bed - legs together and roll
-get a physio and a support belt. Belts are generally not recommended til later in pregnancy, but for some of us they're recommended early, particularly for anytime you need to walk
I am long past the baby stage now, and I'm not as disciplined with those sorts of hip healthy things I used to be so strict about. I have quite a bit of hip instability and pain that I know I need to manage better.