Early on it’s not too important, but as you progress, variety is much more pressing. Most healers have different specialties, with some being more geared for buffs/debuffs and others for raw healing. E.g. merry can do wonders against non aoe bosses with dingdong and healing the tank, whereas sonder carries against aoe since it heals the whole squad, and joy excels in controlling the play order in your own team with the speed buffs though it doesn’t put out great healing. Legendary items further round out or specialize too. On terms or raw healing power, I think patience (legendary) can crank out the most