What worries me the most is that even if you are able to drill out e-torx bolt, you will have tough time removing ball joint itself from knuckle.

If e-torx is rusty enough to sheared it's head off, most likely ball joint is bonded to knuckle as well.

This is like simple DIY job ended up with nightmare. If you are handy, have all necessary tools, and most importantly patience, then try drilling it out. Otherwise, take it to shop if possible.

If you fail on drilling it out, then knuckle + wheel bearing + mine as well new CV boot.

Best of luck man!