Are the strength classes any good for achieving muscle gains?

I don’t like to work out on my own; I only do classes. So if I wanted to build more muscle, would classes like MetCon etc be enough? I’ve heard some say those classes are for beginners and don’t produce real results but I want to hear from people here with actual experience in this.

I understand I need to adjust my nutrition, eat more protein, etc. I’m just asking about the lifting/exercise portion here.