Nobody truly owns any bitcoins..because the ownership is only established when you are able to apply a correct private key in a "send" tx (via hardware device or something else), albeit validation of the private key is possible.
Before that, it is all allegedly. This is in principle, of course.
Even though you may well be correct, isn't that still a bit philosophical and abstract... and maybe it is a point worth emphasizing for some purposes.
If we might assert that the private keys are inside of a hardware wallet, and the bitcoins are not inside of such hardware wallets, the bitcoins are in the cloud.. and ONLY the cloud that is part of the bitcoin cloud.. no other cloud... but then anyone might argue that the bitcoins do not exist in any one place at any one time because it takes a bunch of nodes to say what is bitcoin and which bitcoins are which.. . all of the nodes may well have copies of which bitcoin are supposed to be which, but aren't some of the nodes going to sometimes get out of synch.. or maybe not be running exactly the right software to recognize what other nodes might be recognizing.
I better stop before I even get further out of my depths. and just say, uncle... hahahaha
your bitcoin=Schrodinger cat, which is both alive and dead ( or there and not there) or, according to the many worlds theory, there is one universe where the cat is alive (your bitcoins private key turned out to be correct) and another where the cat is dead (many Universes where you don't happen to have a correct key).
In fact, every time I send a tx, is still feels like a small miracle of the code being right and it "happening".
Albeit, I always have a fear of code/key degradation or outright loss.
Nothing is guaranteed, but bitcoin "mechanics" is probably one of the closest approximations to that ideal.