The products I'm talking about are tens of thousands of dollars, but that's a drop in the bucket compared to the security architect that will set that up. This is not a solution for personal use. If you are in this kind of business, and are honestly clueless, then you probably need to be looking to hire a security director who is qualified to handle this. I'll probably venture to say that only the founder/owner or CFO/controller of the company should ever, EVER have unrestricted access to the vault wallet, and depending on the size of the company then even that will need to be addressed somehow (of which I have no idea the best practice on). The security chief does not need to have unlimited access to this in order to do his job. I'd not trust one who asked for such access.

"Simple" ones start at about 5k but require a proper business to buy and can usually do m of n. If you want to go all out you should write your own firmware module and use that. Those engineers are even more expensive than the security architect.

YubiHSM 2 is $650 or less in volume https://www.yubico.com/products/yubihsm/

YubiHSM2 doesn’t do m-of-n in hardware.