Hello, Sciatica sufferer here too. L5 disc bulge and smashed L4 endplate. I was off work for 3 months earlier this year as I couldn’t sit for longer than 30 minutes. The GP told te they wouldn’t operate as they often do more damage going in.
I managed to find a fantastic physio who has now got me back to (almost) full fitness. A series of simple exercises and stretches have transformed my pain. I was on ibuprofen, dyhydrocodene all-sorts. Now the occasional ibuprofen.
My advice would be to find a decent physio with experience in dealing with back problems.
Oh, I also swapped to a hip pack and ditched the camelback as any pressure on the spine could irritate.
Good luck. You have my sympathy in regards to the pain.