Mighty Emboar has finally arrived, and it is strictly a physical attacker. Surprisingly, it doesn't have Trailblaze, which means it's easy for ground types to take charge. I use the same Arceus from the Primarina raid with some tweaks.

Arceus @ Earth Plate
Ground Tera
Ability: Multitype
Modest, 130 HP, 128 Special Attack, 252 Special Defense
Judgement
Recover
Iron Defense (or Cosmic Power)
Acid Spray

I didn't bother redoing the EVs for this battle.

The idea is to mainly tough it out until there is 90% time remaining. If you can get a partner with Intimidate, that would make things much easier. At that time, Emboar will clear your stats, so you can start buffing you Defense as much as you can. I didn't have Iron Defense on mine, so I had to use Cosmic Power. You will need to Recover in the mean time, especially since you will likely get burned on the way, so you'll want to save your heal cheers.

With enough Defense boosts, I lower its Special Defense to 6 with Acid Spray, then start attacking with Tera Judgement. Once it is at 55% health, it clears its stats a second time, so two more Acid Sprays should help with taking it out with a Tera Judgement.