It is possible for Ranger to be Archer's 2nd Job. Jobs are not based on their Main Stat choice but what kind of Role and skill they provide. Bard may use DEX for their main stats but they focus on being a Hybrid of DD and Support switching between these two roles depending on the situation of a fight in FF14.
Ranger, however, is a Job focus on being more a Pure DD Job in FF series. Its role is put more into performing damage rather than being the supply unit of the group like bard is.
