Many people have good luck with chiropractors. I've never been to one but I understand that they can be helpful.

I'd find another physical therapist myself. If you have a primary care doctor, you could go to one recommended by that doctor. You may already have gone that route since you mention having physiotherapy?

If that physiotherapist was recommended by your primary care doctor, why not tell your PCP that you'd like a different referral because this one didn't help?

I've been for several courses (usually 8 sessions) of physical therapy over the years, usually in connection with sciatic pain that was sometimes as severe as what you're putting up with, and usually the therapy didn't just involve exercise routines. Ultrasound and electrostim were used too, and they seemed to help.

There are good physical therapists and then there are some mediocre ones. I've been lucky in having mostly good ones. I hope you'll get lucky too because the kind of pain and limitations you describe are miserable.