I have had on and off again leg cramps over the years, sometimes from different causes (RLS, sciatica, vascular). I have not tried magnesium but have heard before that it can help. Otherwise, my approach has been hydration, elevation, compression sleeves, avoiding alcohol too close to bedtime, stretching, and I take a prescription for nerve pain.

When it has come to sciatica being a contributing factor, proper support between my knees, under or around my spine, and under my head has helped a lot. Also if a neurological cause is suspected, stretching the hip muscle groups can help because sometimes the muscle that crosses the sciatic nerve is spasming. (For me, my sciatic pain is from my calves to my toes.)

For vascular causes, evaluating your exercise routines may help. I would do this in consultation with your doctor (especially if you have other conditions). Something like yoga can be gentle, but also very beneficial. Yoga has many different styles and levels - there are instructional videos on Youtube. For example, if you need an easier version, look up chair yoga.

Hope you feel much better soon!