Post-rotation Radiant Eternatus/Single Strike

WAT

This deck is good, it would seem that in mirror matches with non-single strike based Duraldon VMAX it would lose, except that it's attack "isn't affected by any effects on your opponent's active Pokémon", so I assume that that would break through the opposing Duraldon VMAX's ability.

Octogenarian you are correct, the attack does break through the ability. In fact, it also breaks through miltanks immunity! 
As for how this deck works, I'm am sure that you can't actually accelerate impact energies onto duraludon, so that's a problem. The other thing is that you don't actually have to add so many copies of duraludon v, thanks to radiant eternatus skipping the evolution. It would also help if you could get rid of the gapejaw bogs and add zigzagoons instead, and also add single strike scroll of scorn as well.

Manaphy would be cool but looks sick

Pokeregidrago I agree, I was just thinking maybe just 1 or 2 duraldon Vs, and thank you for clearing up the ability/attack thing! However, I think that wouldn't you be able to attach energy to Duraludon VMAX because he is a single strike?

I think it still possible for the energy attachments to be very consistent but the impact energy, even though it is single strike, is not considered a single strike energy. This is because it has the name impact energy instead of single strike energy, so the energy acceleration would be a bit slow in this deck. So i dont really know the best energy acceleration for duraludon except for Arceus Vstar, but this deck works fine!

I still don't understand why there are baby urshifu and a dark energy.

lance seems like a waste of a supporter as you are only getting Eternatus when you could just get him through nest ball (coming in S&V) or ultra ball?

you could also get duraludon

guys pls look at my deck https://pokemoncard.io/deck/best-budget-deck-37366