I am guessing you have done lots of research on femoral nerve entrapment like I did and tried it all.

Bust what does help me are stretches to floss the nerve just look it up on YouTube, I think I suffer from mine because I am overweight and like to hyper extend my hip flexors like most overweight women, try and be conscious of not tilting your pelvis forward when you walk as this entrapment the nerve more.

When mine gets bad I like to put a heatpack on my hip and an ice pack just above the knee.

Ian find yourselves a good physiotherapist that can work on posture

I hope this helps