Increasing DPS

I’m playing a Stam arc cp lvl 428 running deadly strike + tide born with slimecraw helm (haven’t got the shoulder yet)

Been wanting to really focus on increasing my dps to get a taste of running vet dungeons in the future but I used a 21m dummy and managed to only get 40k dps. With the set I’m running is that normal? is it really a rotation issue at this point?

What should I be looking out for ?