[ojilles]

...but not that many that guarantee/clarify if something was read/duplicated. That’s what a safe would buy you.

[viraptor]

No, I really mean "many ways". Just search for tamper evident products. There's a huge number of ways you can get that guarantee. For example this: https://harcor.com.au/products/security-seals/tamper-evident...

[ghaff]

Lots of ways to set markers against all but seriously professional adversaries. I’d personally worry more about losing access to your key/combination.

Frankly your main threat is probably a fire or flood. Not a Russian agent breaking into your house.