It's a very good question. Perhaps the best multi-sig is to use three different devices from three different vendors. That's not an easy setup though. BitKey makes it easy.

Re. (3)... NO!

This. This wasn’t a cold card problem… this was a putting your trust in the vendor software problem. I would argue leaning heavily on something like bitkey actually makes this worse. Yes it solves other problems, but this same exploit can, and will, happen to other vendors. Actually… didn’t...