NatDex Ubers: Dragon/Flying Spam HO

I've been getting into National Dex Ubers recently, and the tier can be quite fun to play despite things like Smeargle Webs existing. and the ladder being so unserious. I wanted to use Mega Salamence and Rayquaza, so I decided to build this HO team with both of them on it. I found these two to work quite well with each other to overwhelm shared checks so one can clean late-game. This team is built around the offensive core of Mega Salamence + Rayquaza. The team has performed decently, though there are some concerns that I have with this team. Here is the Team Pokepaste if you want to try this team out.
Deoxys-S

Deoxys-Speed @ Covert Cloak
Ability: Pressure
Tera Type: Steel
EVs: 248 HP / 8 Def / 252 Spe
Timid Nature
IVs: 0 Atk
- Stealth Rock
- Taunt
- Magic Coat
- Spikes
The lead of this team. I decided to go with Deoxy-S due to it being the fastest HO lead. The moves are standard, but the item I have isn't. After being fed up with Smeargle's Nuzzle, I decided to go with Covert Cloak just so it won't paralyze me, and it works surprisingly well, especially with Tera Steel and Taunt to shut down Smeargle completely. Part of me wants to slot in an attacking move like Psycho Boost over Spikes just so I can actually damage Smeargle without having to switch out. Should I do that, or should I stick to switching out to damage Smeargle if the Smeargle user decides to stay in instead of switching out?
Mega Salamence

Salamence @ Salamencite
Ability: Intimidate
Happiness: 0
Tera Type: Dragon
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Dragon Dance
- Frustration
- Earthquake
- Roost
One of the two Pokemon I built this team around. Pretty simple sweeper set, with Earthquake targeting Steel-types such as Necrozma-Dusk-Mane and Zacian-C, as well as hitting Pokemon such as Eternatus and Primal-Groudon since I don't have Double Edge as the STAB move on this Mega Salamence set. I went with Frustration over Return on this set so I can deny Ditto (that aren't 0 happiness) joy and happiness should it try to come in and copy Mega Salamence. I find that the loss of power from Double Edge isn't that bad since Mega Salamence also has Rayquaza to overwhelm shared checks for it.
Rayquaza

Rayquaza @ Life Orb
Ability: Air Lock
Tera Type: Flying
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Dragon Dance
- Dragon Ascent
- Extreme Speed
- V-create
The second Pokemon I built this team around. Mega Salamence + Rayquaza form a really nice offensive core together, being able to overwhelm shared checks so one of the Dragon/Flying-types can sweep late-game, with the other one opening up holes in the opposing team early-game. With Dragon Dance, Rayquaza becomes a threat due to its coverage. Dragon Ascent paired with Tera Flying is a nice way to deal Pokemon such as Ho-Oh, Eternatus, and even 2HKOing Dondozo. V-Create being able to get rid of Steel-types such as Necrozma-Dusk-Mane and Zacian-C is really nice, as well as being able to hit Tera Steel Giratina-O, a Pokemon that checks Mega Salamence quite well.
Primal Groudon

Groudon-Primal @ Red Orb
Ability: Desolate Land
Tera Type: Ground
EVs: 140 HP / 252 Atk / 116 Spe
Adamant Nature
- Rock Polish
- Swords Dance
- Precipice Blades
- Heat Crash
With Mega Salamence and Rayquaza's huge allergy to ice moves, as well as their weakness to Fairy moves, I decided to add dual dance Primal Groudon to the team. Primal Groudon is nice as a check to Pokemon such as Zacian-C, Eternatus, Necrozma-Dusk-Mane, and even Primal Kyogre to an extent. In turn, Mega Salamence and Rayquaza can switch in on an incoming Ground move in a pinch. Dual Dance Primal Groudon does nice at sweeping teams or opening up holes for something else to sweep. I went with Heat Crash over Stone Edge since I wanted an accurate STAB move, and I feel like Mega Salamence + Rayquaza already do a good job at overwhelming Ho-Oh. Plus, having Heat Crash is nice to hit Giratina-O should it Tera Steel to check Mega Salamence. The EVs is the standard dual dance spread, with the Speed EVs giving Primal Groudon enough speed to outspeed Choice Scarf Yveltal after using Rock Polish.
Yveltal

Yveltal @ Life Orb
Ability: Dark Aura
Tera Type: Dark
EVs: 4 Atk / 252 SpA / 252 Spe
Naive Nature
- Dark Pulse
- Oblivion Wing
- Sucker Punch
- Taunt
I decided to add Yveltal as an offensive check to Pokemon such as Necrozma-DM and Marshadow. Yveltal is also nice for dealing with Giratino-O and Lunal pre-tera. I went for Sucker Punch over Knock Off to allow Yveltal to pick off faster Pokemon such as Marshadow and boosted Ultra Necrozma/Necrozma-DM. Taunt is nice to be able to stop setup sweepers from setting up, and is useful to stop Defoggers like Ho-Oh and Giratina-O from removing hazards set by Deoxy-S.
Necrozma-Dusk-Mane

Necrozma-Dusk-Mane @ Ultranecrozium Z
Ability: Prism Armor
Tera Type: Psychic
EVs: 40 HP / 248 Atk / 80 Def / 140 Spe
Adamant Nature
- Dragon Dance
- Photon Geyser
- Earthquake
- Stone Edge
For the last slot, I decided to go with Necrozma-DM as an ice resist pre ultra burst as well as a Zacian-C check. Dragon Dance Ultra Necrozma is scary sweeper that can clean through teams or weaken them for a teammate to sweep. Earthquake targets Pokemon such as Zacian-C, Primal-Groudon, and Necrozma-DM. I decided to go for Stone Edge to immediately threaten Ho-Oh, though I'm wondering if I'm able to use another move over Stone Edge. The EV spread used lets Necrozma-DM outspeed Chi-Yu after Ultra bursting as well as Scarf Yveltal after getting off a Dragon Dance (after Ultra Bursting). The physical bulk investment allows Ultra Necrozma to survive a Banded Marshadow's Shadow Sneak provided you have enough HP and have a decent chance of surviving a +2 Arceus' Extreme Speed from full. The special bulk lets Necrozma-DM survive an unboosted Fire Blast from Eternatus.
Problems/Concerns
- I find Arceus-Dark (or Darkeus) to be problematic, especially if its the defensive set with Foul Play, as this team is basically physical overload, and if it has Taunt, Rayquaza and Primal Groudon won't be able to setup.
- On the topic of physical overload, Coil Zygarde is also a problem, as I don't have any other special wallbreakers other than Yveltal. Any changes I can make to make this not a problem.
- Ice moves are also a problem, since half of my team (4 once Necrozma-DM ultra bursts) are weak to ice moves. Are there some changes I can make to the team to make this not as big of a problem?
- None of my Pokemon aren't as fast without boosting. Should I change the Yveltal and/or Necrozma-DM slots to address this issue?
- I'm considering adding Zacian-C over Necrozma-DM so I can have a fast Pokemon that naturally outspeeds Pokemon such as Marshadow and Eternatus, using this set:
Zacian-Crowned @ Rusted Sword
Ability: Intrepid Sword
Tera Type: Ground
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Swords Dance
- Play Rough
- Tera Blast
- Wild Charge
Should I make this change? If so why? If not, should I use another Pokemon or is Necrozma-DM fine?
And that's all for now. Looking forward to making improvements to this team, as I have fun using it. Thanks for reading!