I'll say that such a thing is possible in dreams but not in real life so thinking what I'll do with something that's not possible to have is no less than stupidity I guess. Let's say even if someone somehow gets access to a wallet's private key filled with $100 million worth of Bitcoin then that's no less than a jackpot. I think the best that person can do it to donate the money in charity so he/she won't face any issue whatsoever. However, such amount can be quite risky for someone with no security because if negative people find about such thing then the one who found it will be in danger.

Well I have never heard such a thing happening before, which is why I think it’s just a made of story, but this can possibly happen, because someone who have bitcoin stored somewhere in a wallet can accidentally loose their life, and nobody have access to their keys, but I’m wondering how you can possibly guess someone’s passkeys perfectly.

Judging from what you have said, I must say you’ could be a very generous person, because how do you think about creating a Topic here for someone to claim the money as the rightful owner, how about if the rightful owner  isn’t in the Forum or dead and nobody can claim it in the forum or any other place, what can we do about it in such a situation that you’ve made that efforts.

If that is not yours, you should not use it and just keep it. You know that break the law because you use something that you don't own. But I am not sure because seeing the wallet contain $1+ Billion USD balance could tempting someone to use small portion.  That is your call whether you want to use it or keep it.

But I wonder how they get the wallet? If they steal the wallet and all info, they stolen the funds and that breaks the law. But that will be a big jackpot for those people

Hasn't this, in some way or another, been asked a thousand times or so here and at other places where crypto coiners or Bitcoiners in particular are lurking around?

In the first place while it's mathematically possible, it's practically impossible to stumble (or guess) a private key that still controls unspent funds. Probability is so close to zero that you can say, it's basically zero. Babbling anything else is nonsense or you don't understand how Bitcoin works.

Guess what, all private keys are already known, starting at
0x0000000000000000000000000000000000000000000000000000000000000001
up to
0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364140 (hexadecimal here, apparently).
(Source: any decent documentation of Bitcoin and its secp256k1 elliptic curve, max. is order of finite field minus one)

What you don't know, except for your own private keys you control, are any other private keys that still control any funds that aren't yours, be it a few Satoshis or funds equiv. to one billion bucks as OP's citation suggested to babble about.

If you need a picture (which is still not imaginable due to the huge numbers involved). Imagine Bitcoin as a bank with vaults like shelf boxes, only that those vaults are completely open, they have no doors. Every Bitcoin private key is one of those vaults and every vault can contain multiple coin chunks aka UTXOs. Our imaginary Bitcoin bank now has a "wall" of vaults, almost 2¹²⁸ times 2¹²⁸ open box vaults. Almost all are empty, only a tiniest fraction of vaults are filled with coins, I repeat, no doors.

Technically anybody could reach into such a vault that isn't yours and grab the coins therein. It's morally wrong and if it's lawfully wrong, that's on your country's jurisdiction or that of the vault's legitimate owner (or both?).

My point is, you don't have the time or energy to find any filled "Bitcoin vault" (with decent entropy aka "vault number") that isn't yours in the first place. I believe it's pointless to fantasize about "what if you stumble over a private key controlling $xxxx equivalents".
It simply won't happen in your lifetime, the lifetime of our solar system, of our galaxy, the universe...  Period!

This is going to be interesting, haha. I think if anyone luckily finds or cracks any private key of a dormant wallet.
Then this can also be considered a hacking act, no matter whether you guessed it randomly. Your part of the story will be that you guessed it randomly, but authorities will consider it part of a hack and illegal, haha. Like, let's say you get that money and use it to buy homes, planes and cars.

And when authorities will notice your lifestyle changing so fast, then they will dig into the matter deeply and try to catch you. So that they can take that money into their custody. But I am sure whenever they will siezed that money from you, that money will also fall victim to corruption. Their target will be just that; in any way they get that money from you, haha. This is my point of view. CMIIW!

Here, every question has to be answered strangely because if someone can match the key of a Bitcoin wallet worth a billion dollars, then I can definitely say that it is a coincidence and unrealistic event. Although I do not know whether such an event is happening till date, but if it happens in life, then I will definitely say that it is a miracle. However, matching Bitcoin wallets is not a crime because in this case, if the owner of a Bitcoin wallet is dead and later someone can match the key of his wallet, then it is undoubtedly legal. I do not see anything criminal here because the owner himself is dead and no one could access his wallet. Then I must say that if someone can match the wallet seed phase of that dead person, then he can definitely use it.
Actually, this is an unrealistic event and I am expressing my opinion on that event which is actually never possible.

When the security seed phase of a wallet is in the hands of someone, that person is essentially the owner of that wallet. Now basically if more than one person has the security seed phase of a wallet, then if more than one person claims to be the owner of that wallet, then legally everyone will have to be declared as the owner.

However, in my case, if I could match any wallet, then I would definitely go offline from online for the rest of my life with that much dollar.

Since it's a guess, no one can actually blame you for that but, your good conscience should tell you it's not your coin and you shouldn't transfer the coins in that wallet to any other wallet of your choosing. For what is worth, the owner might just be holding it there all along and having to transfer it would constitute theft even though you might not be caught since, it wasn't on any exchange that has your KYC documents.  By the way, you shouldn't go about guess private keys if you don't have ill intentions before proceeding to the activity.

I doubt it someone can successfully guess or brute force a private key that contains that much. The situation might either someone who's got a flash drive that has saved keys or files in there and able to recover when it's opened not knowingly that there's some btc in it from the actual or former owner. I don't think that there are laws that can indicate into the situation not unless the one who has given that will contest it and there goes the dispute which can happen. Someone who recovers that amount is fortunately and that's a life changing money that can put him into retirement.