This is a very old problem. One of my first commercial programs was a wordpress plugin and as you know, you just distribute the PHP source code in a zip file and there it is

You will never sue your way out of this. Piracy will always exist. GitHub will respond to a legal notice but whack a mole is the game and legal notices cost money

The solution in the WP community at the time was variations of the plugin as a loss leader to get revenue with support or to leverage community visibility into larger contracts for work or hosting the platform for others.

If your business model depends on your code being a secret, JavaScript is not a good play. The business model needs to enhance what the code offers since it’s basically a commodity now