Then, everyone who trusts the CA will trust your certificate by checking it is signed by the CA who should have done the checks to ensure your certificate contains truthful data.
So your layman description of “they have secret codes to everyone’s encryption” is completely wrong.
A modern TLS connection uses an ephemeral key-exchange protocol where both parties opaquely agree to a one-time-use random encryption key that is not knowable to any other party, not even someone who can gain access to either party's private key. This is called Forward Secrecy (originally and sometimes still known as Perfect Forward Secrecy or PFS, but the use of the word "perfect" in any cryptographic context is akin to naming a ship "Unsinkable").
> random banks and IT companies in the world holds the secret codes to everyone's encryption.
That's not true at all.
What they do have is the power to MITM connections IF they first spook DNS or insert themselves into a proxy accepted by the server somehow.
So, if you want to be honest, the original sentence becomes:
> random banks and IT companies in the world holds secret codes that are trusted by everyone to sign information that is used to establish trusted communications. If they wanted to, they could try to tamper with people's network connections and, if successful somehow, pretend to be anyone else that had used their secret codes to sign their information.
Quite a big difference, no?