How is it a miracle that you have a private key? What you say is not true; unless you are a hacker, that can happen. But the fact that you can discover a private key for Bitcoin is an impossible thing, unless you have a friend who you know is in the field of this industry.
And let's assume that what you said is true. Is there any news of something like that happening in the crypto space that returned a large amount of bitcoin because he discovered a private one that he got in a paper wallet, or a hardware wallet, or maybe in the files of a flash drive?
As in the story of a hard drive being thrown away and someone finding it, it can happen.
But if finding a random private key would be impossible, no one can penetrate a Bitcoin wallet with any random private key even though he is a hacker, it even takes a super computer to brute force, and it takes hundreds of years.
In response about the OP's question, directly if someone has a private key, then it is his/her because you can control it.
But in ownership it belongs to someone else, and you need to find out who owns the wallet.