My suggestion to you

Play the job you like and not the job the game needs

If you don't know what you like then play all of them but just from reading your post, you are more or less either bard or a red mage player

Bard sing song while dps they increase direct hit chance and they also reduce damage for a player and they also give mana to the party mostly healer will benefit most while at the same time doing high amount of damage, another cool thing about bard is that they usually have the coolest looking weapon in the game

Red mage - they are dps support unlike bard, they give damage increase to the party and they also help raise dead ally when they get killed from battle which will help the healer stay focus on healing instead of raising and they also can heal quite a bit of hp to an ally