Though you have shot a hole through the argument it doesn’t get full credit. The opener of the thread asked to make a choice between the two. So it becomes a dogmatic question as well not just behavioral. For a muslim salvation is not just linked to humane behavior but also certain belief and doctrines.
The quest to become a better muslim includes ones attempt to strive for being a better human being inherently. Whereas one striving to be a good human being does not necessarily attach to a doctrine or belief.
Being a better human being is devoid of belief but rather based on practice of humane behavior for most part. A person of absolute malicious intent can also prove to be a good human being by simply engaging in humane activities.
Again the questioners intentions are unknown.