What is the best process and material for a crown for a bruxer? Gold, zirconium, ceramic, a combination, etc?

Tooth is a bottom right molar and has a root canal, defective crown, & multiple cavities under crown. Cannot afford to lose this tooth because it's on the main side of the mouth I chew on. I am a bruxer and seriously grind teeth at night (the crown on the root canal tooth has the enamel worn down, it's just metal). I am about to treat severe osteoporosis with bisphosphonates & need something with very tight margins on the gum line, extremely durable, will last & not get worn down or break, etc.