Not enough dps

I’m shadow and wondering what I’m missing. I see other shadows in bg’s that’s doing twice the dps with comparable gear.
I’ve been told twice in the last week that I’m not doing enough dpsin arena . If I wait until my insanity bar is full to get the best burst, then no problem if we win, but if we lose its, why weren’t you bursting?
If I come out of the gate, straight into burst, then it’s not my best burst because I don’t ha e insanity yet.
On top of that, I have to watch for pally bubbles, life grips, swaps, off heals and everything else.
In bfa as a new sp, I got to 1.9 in 2s and up to or around 1800 in 3s and that’s when sp wasn’t as good…so fellow spriests, what’s the strat? What’s the rotations? Any thing at all would be helpful. Thanks

What are you doing in arenas and bgs to do damage, in between burst windows, and during burst windows?

ST in arena:
I hit them with the talent that instantly puts all 3 dots on my target, then hit the off target with my instant proc of 3 dots.
Back to my kill target:
Mindflay and MB’s only if I get the instant ones. When I get to about 75% insanity I drop my pet, power infusion, then erupt, void bolt…cc/silence the healer then mindgames my kill target void bolts on cd, mindflay in between and pop MB’s if the proc, sw:death when it procs.

That’s my ideal situation anyway

Edit: after I silence/fear the healer, I stun my kill target right before mindgames