Sacroiliac SI Joint Pain Exercises for Powerlifting Rehab

I have developed some localized pain right over my SI joint on the left side. It usually flares up during heavy sumo deadlifts and it makes it hard to even walk the next day. I have been to a chiropractor but the adjustments only seem to last for a few hours.

I have started doing more unilateral work like split squats and single leg deadlifts to see if that helps with the stability. I also read that core bracing is huge for SI joint issues. Has anyone found that the McGill Big 3 or specific pelvic floor exercises helped them lock down their SI joint?

I am trying to avoid any movements that cause a shift in my pelvis. It is a very annoying injury because it feels like a small misalignment but it causes so much dysfunction. Any advice from fellow lifters in the UK would be much appreciated.