Sorry you’re going through this it’s so terribly painful watching our paws in pain isn’t it.
My dog (12) was diagnosed with arthritis in her hips. She was given loxicom at first which did nothing then a combo of loxicom and gabapentin (2 x 100mg a day). First flew days she was spaced out, literally flopping on her bed, having accidents, rolling eyes etc but that settled down and she did regain some mobility and I think it eases the pain (she was alert, out of bed, walking round etc) and sped up a little on her walks. I did notice though her appetite dipped a little at times.
After some discussion with the vet we’ve tried librella, not because previous weren’t working but because long term they can have effects on liver and kidney function, plus they wear off. So we found she was stiff / suffering more at times tablets would be wearing off, whereas librella is constant (lasts for 4 weeks from injection) and doesn’t have known long term side effects.
She’s been fine, noticeably less stiff at certain times, and appetite back to normal.
Also have you tried yumove ? This was recommended to us and she has been on this too. Honestly the difference has been unbelievable. She’s gone from being shakey, unsteady with buckling legs at times to gaining strength and stability, improving her walking speed