Been messing around with the deck, I have access to fully developed Mewtwo, Pikachu/Raichu, Charzard/Res, Malamar/UltraN meta decks and a Spirittomb/Frostlass deck to fight against at home with the kids.
So far I can't beat the Pikachu/Raichu deck at all. Just gets stomped.
I've been fiddling with some alterations from your design in order to fill in some small gaps in my personal play style and what I see problematic in my plays. It does create a secondary issue revolving around Energy use tho, which I am working on.
The 1 prize being an evolution is a hard one in my tests, usually it ends up being communicated for more damaging options. I already have to evolve the eevee's in order to get my glaceon going, and I need to evolve a second Eevee because the first one is simply not going to last long in this meta.
I searched for something that could work as a basic 1 prize and came up with a few changes that have been given me some good consistent benefit over the OPs choices.
I ditched 1 jirachi
I ditched Articuno GX
I ditched Seel and Dewgong
giving me 4 cards to change.
Swapped the basic Eevee for another Eevee GX so cherish ball had more search ability for my evolution, and i could always communicate one of the eevees if need be.
I added in 2 White Kyurem as my basic attacker, added 1 Water energy and 1 Cyrus supporter.
The White Kyurem works well with the welder engine adding fire into a blue deck, and at the same cost of Articuno's attacks it offers 1 less prize, and does more damage.
I have the same amount of alternative attackers as your Articuno/seel/dewgong was doing at 1 prize and 1 card less, and more damage out put for general attacks overall.
I do need to invest extra water energy to run both of my White Kyurem (4 blue 2 red) over your Articuno/Dewgong (2 blue, 3 any) combo but I'm trying to account for that with the extra energy in the deck. The cost of running two White Kyruem in a game is detrimental over all when we only have 5 water energy and 7 Fire energy. a 6 / 6 split might need to be tested. Or replacing one of the White Kyurem's with a 1 blue basic attacker. Replacing the Cyrus with a water is another option, thinning the supporter use.
Cyrus I found very useful early/mid game but quite useless late game. I won multiple games by trapping the opponent into 1 pokemon and winning because of it.