Yayz, it's pudding cup from SDA
! Welcome here dude.
For the deck, luckily for you i've been playing with Rock Stun lately so I can help here. In stun you don't need many monsters, but with the Koa'ki Meiru and their maintenance effects you need slightly more than usual. I've found 17-18 to be a good number, preferably 18. Second, the skeleton of your deck should be 3 KM Guardian, 3 KM Wall, and 3 KM Sandman. They're pretty darn pro man, and they have 1900 atk so what's not to love in a stun build? Third, you forgot the best rock eva: Fossil Dyna! He's as pro as hell in stun anyway, and it's made that much greater here by being a rock. Run 2-3. And fourth...a rfg rock deck with no Dimensional Fissure? *Scratches head* That's kinda the whole point lol. Drop those Soul Releases for a much more large encompassing card. They make your Release From Stones more active too. The idea of RFG Rocks is that the stun cards you have don't care if they hit the grave or rfg...so **** up the opponent by removing their stuff. Imagine if you played this against Fabled, Dark World, or Junk Doppel! They couldn't do crap xD.
So those were the major flaws I saw, here are my fixes now:
-3 Gigantes (not a bad tech really. But this is stun so you'd probably be nuking your own backrow most of the time and plus with Fissure now there won't usually be anything to remove...)
-2 Gaia plate (same reason. You have no grave now lol)
-3 cyber valley (no real reason for them and they ain't rocks so bb)
-2 rockstone warrior (fossil dyna is far more pro)
-2 gren maju (eh. Maybe side but they're not rocks...that's the main thing bc of the KM and Release From Stones)
-2 ddwl (good but I like TKR better)
-1 gale (see above)
-1 gorz
-2 soul release
-1 Econ (meh card)
-1 mind control (you don't synchro...lol)
-1 nobleman (side deck card)
+3 km wall
+3 km sandman
+3 thunder king rai oh
+2 fossil dyna pachycephalo
+2 mystical space typhoon
+1 book of moon
+3 dimensional fissure
+2 solemn warning
+1 seven tools
That should do it. Maybe Reborn...but with Fissure idk yet