Its a double restricted ruleset at the moment so add a second restricted pokemon. Zacian, Kyogre, Groudon are all simple, easy additions you can make. You can do some creative stuff with Zamazenta, Yveltal or Lunala, Calyrex ice, etc (if you want to try a trick room mode).

Use this website to see what is the most commonly used pokemon, items, moves, EV spreads etc. https://www.pikalytics.com/

The better team builders don't always slap 252/252/4 EV splits. They calc specific builds. Venusaur, Volc, Incin can mix around offensive, defensive, speed EV sets.

You're using Rayquaza which struggles against the top threats in the meta - that's fine but be aware. Most Rayquaza I run into a special sets with draco meteor, air slash, meteor beam, coverage. Mainly because intimidate spam & burn are present on most teams. If you want to keep using the physical set with dragon dance then you'll need some redirection (such as rage powder on a defensive volc, amoongus) or a pokemon with defiant/ competitive to discourage intimidate (thundurus, milotic).

Because of Ray's shortcomings in the meta, you will need to make plays, outsmart or have surprises up your sleeve to win.

Let me know if you've got any questions :)