Core Stability Help

Looking for a routine I can do to improve core stability while continuing to lift weights. Sciatic pain keeps coming back. Already had one surgery for a herniated disc but trying to avoid spending the money for physical therapy every week if I can figure out how to solve and prevent this on my own. Doctors have helped the pain disappear with surgery/steroids but I need to start focusing on the root cause so i can prevent it from coming back.

From reading squat university I'll start doing curl-ups, side planks, and bird dogs.

I think, not certain, that my lower back issues are with flexion and when extension is paired with rotation. I also know that I have some limitations in dorsiflexion in my ankles. I really don't have much lower back pain at all, just the sciatic pain in my butt and down my leg