Ideally yes, maybe not necessarily (for a scudetto). More than enough examples of players, who were not in that category when signed, that lifted a top team.
Then you can maybe count them in that category afterwards, I guess... But I'd start with signing reliable performers instead of those hot-'n-cold guys. Someone like Locatelli falls into that category with room for growth. De Paul is relatively expensive as he probably won't develop much further and is looking for a big contract at this point.