This is what I learned over the years after my techno fantasies were confronted with the real world. Technology can give you good protections to make blanket or mass interference on people’s affairs costly, but the illusion of safety it gives is over emphasised.
A very motivated actor will just knock on your door and ask you for the key(digital or otherwise) at gun point and it is game over.
Like one of the replies above, model your threat and enjoy like free of paranoia. It is a beautiful world out there! Ah and be politically active so your representatives preserve common freedom and well being.
Locksmiths will get through that lock in a couple of minutes, probably without you ever knowing
The only thing stopping the bank and/or government from accessing your box is the law