If you don't want to go to so much trouble, take a positive attitude and make peace with Orpheus.
3. Are there any other defense methods, such as legal sources, which can provide invoices, samples or sample books of suppliers (enough to show that the products on the invoices/sample books are the products involved)?
This kind of lawsuit, after the other party sued, requires a low amount of compensation; If the patent application is invalid or you hire a lawyer yourself, it may cost more than 3W, so that the plaintiff will seize the defendant's heart that he doesn't want to spend more money and finally get a family ~