I'm in the same boat (a mid-tier S+ player) I use range blaster and chargers. I watch Sendou on youtube and team olive stuff. Other players like rocketek as well. It's to my understanding that swim speed is great, in recovery, (it takes forever to start getting ink so you want to get as much out of it when you actually do), bomb defense, etc. I use comeback, ink saver main, swim speed, bomb defense, and a couple subs of ink recov. I don't remember exactly how it's all configured though. Coming from a support role (chargers) I tend to struggle with getting out there but I see a lot of people just sharking everybody. It's a slayer weapon and I have good aim so directs aren't too difficult for me (probably the most important skill to have).
TLDR: It's a slaying weapon, terrible at turfing so kills are your way of coverage. Use basic movement and close-range survival abilities (To my understanding)
I try to replicate this as much as I can to be better at the range blaster, but then again I'm just an average S+ player so I'm still working on it myself
EDIT: If you can't get directs then that's the first step. Directs fuel the insane gameplay you see professionals do