SAFE way to convert YouTube to wav or mp3 for use on iTunes library

From what I've read, pretty much every converter is risky except for the one that's built in on YouTube Premium. All of the other converter apps (free or not), but especially the free ones, have access to your computer and will snoop around if they want to. A virus is not as likely, but snooping or phishing definitely is. And you'll never know that they're quietly snooping in the background while you're enjoying their converter! Unless someone here can assure me otherwise, I'm probably going to play it safe a pay for YouTube Premium to make my conversions.