What should I do if the protagonist’s name in a novel is the same as the protagonist in someone else’s novel?

Change the name...

Otherwise, change the word to have the same pronunciation.

Otherwise, there is no need to change, just highlight that the protagonist’s personality is different from others. .

And in fact, the protagonists in many novels have the same name.

Of course, if you want to be different, it is better to use different ones.