How do Protestants who say Catholicism doesn't teach the true Gospel understand a Catholic person’s faith in Jesus?

On Protestant theology, Sola Fide is understood as: > Sola fide—the doctrine of justification by faith alone apart from works—is simply recognizing what is taught over and over in Scripture—that at some point in time God declares ungodly sinners righteous by imputing Christ’s righteousness to them But I hear many Protestants, such as John MacArthur, who claim that Catholicism doesn't teach the true Gospel: >As long as the Roman Catholic Church continues to assert its own authority and bind its people to “another gospel,” it is the spiritual duty of all true Christians to oppose Roman Catholic doctrine with biblical truth and to call all Catholics to true salvation. But how can this be? I think that every (faithful and informed) Catholic you meet on this site and in real life will say that they have faith in the resurrection of Christ and his teaching. So on the view of Sola Fide, can’t Catholics still be expected to go to heaven since they express faith? Or am I missing something here?