https://www.makeuseof.com/original-melody-avoid-plagiarism-tips/

The article mentions songs that have not been recorded or publicly performed. I would think it is hard to prove someone stole your melody its never been heard by anyone. I guess it could happen accidentally. But most cases is as was mentioned at the beginning, you hear something then years later it pops out of you and you don't realize you heard it before.

Ridiculous nonsense by an armchair "expert". Most of those methods will not work.

I know I have come up with original melodies in the past, only to have it pointed out that it sounds like XXX by XXX

A number of interesting scenarios, but ultimately could be analyzed as "Precision Guesswork"

From that website - "Unless you're one of those geniuses who can make music by ear without knowing a thing about music theory"
Does that make me a genius LOL!

This thread is about melody!
A chord progression cannot be copyrighted.

Yep—neither can ideas or titles.

Not that people don’t try…

If you have created a melody and are concerned that it may be similar to an existing copyrighted melody, there are several ways to test it:

Conduct a thorough internet search: Start by conducting a thorough internet search to see if there are any existing songs that sound similar to your melody. This can help you identify any potential copyright issues.

Use a music recognition software: You can use music recognition software such as Shazam, Musipedia, or Midomi to see if your melody matches any existing songs. These tools compare your melody to a database of existing songs and can help you identify any potential copyright issues.

Hire a musicologist: A musicologist is an expert in music theory and history who can analyze your melody to see if it is similar to any existing copyrighted melodies. They can provide you with an expert opinion on the originality of your melody.

Consult with a lawyer: If you are still uncertain whether your melody may be infringing on any existing copyrights, it is recommended that you consult with a lawyer who specializes in copyright law. They can provide you with legal advice on the matter and guide you on the best course of action.

It is important to note that even if your melody is not identical to an existing copyrighted melody, it may still be subject to copyright protection if it is substantially similar. Therefore, it is always recommended to conduct a thorough analysis before releasing any original music.

This is absolutely guaranteed to fail. Such software compares the first few seconds of recordings agains a database and cannot identify melody.

Certain popular loops will pop up hundreds of matches in Shazam, for example. The PROs use such apps to listen to the internet and determine what is being played where. For this reason, one should never use a commercial loop in a released recording unless heavily edited enough so that Shazam cannot recognize it—you want your work to be properly identified and credited.

BMI may or may not still use Shazam. They bought it from British Telecom and owned it till 2012 but had to sell the app when it became profitable and threatened their non-profit status. Ooops! After a few other ownership changes, Apple bought it and is the current owner. ASCAP, SESAC, GMR and the others use similar apps, some of which are proprietary.