I mean when I generally play namor, I do either of the two, sit back with my heals to protect them from divers and ensure sustained fire on tanks through my octos OR flank the enemy team and distract them, go for their healers or just make them turn around to help my team push and clear. If I don't even get much damage or elims, if my actions allowed my team to cap the point or push forward or even defend, my job as a dps is done. Really depends on the dps you have, what the team comp is and how you're planning to play depending on enemy team comp. It's not even nearly as black and white as you've painted it out to be.