Methods are pretty much fair game. I’ve never had that be an issue at all, not even a potential one. The only thing that would be trouble is directly copying code from a private company repo.

If you’re in cybersecurity and some of those methods are non-obvious and knowledge of them could cause your company or its clients some vulnerability, then it might be a different story.

But at least in the places I’ve worked, absolutely none of the coding methods, design patterns, techniques, etc were considered trade secrets. Only the specific contents of the codebase were special. Like if I worked for Stephen King the only thing that would get me in trouble would be copy pasting one of his works. Using italics for thoughts like aha now we’re in business wouldn’t get me in trouble.