Radiant Zard is so strong it makes me wonder a little if they actually play tested it beforehand. Raihan + Twin + Magma Basin lets it swing as early as 5 prizes (a little unrealistic in standard.) Raihan + Twin Energy lets it swing at 4 prize cards. Raihan/Magma Basin + any energy at 3, and it swings for 1 Fire energy at 2 and 1 prize left.
The fact it OHKOs every VStar with a Choice Belt cannot be overlooked. We’re talking 1 prize remaining Galarian Moltres level of damage output at realistically 3 prizes remaining. The way I see it, it feels a little like baby Buzzwole and the other Ultra Beasts.
Radiant Greninja provides consistency throughout the course of the game but Radiant Zard gives you a huge power spike mid-late game that virtually any deck can take advantage of. Arceus? Sure. Palkia? Probably would prefer Greninja but it also wouldn’t kill you to Star Portal onto Radiant Zard. Hisuian Zoroark? Yeah, the damage from Magma Basin pairs with Hisuian Zoro and you already run Double Turbo Energy. Inteleon toolbox? Just slap a Fire energy into the list and enjoy your shiny new toy.
I know the inclusion of Radiant Venu in Hisuian Arcanine is the obvious choice but I think Radiant Zard is the stronger choice as it gives the deck the ability to randomly KO a VStar when it otherwise couldn’t have.
The only things I dislike about it is that Rescue Stretcher isn't in the format so you have to Klara or Rod + Ball search it back and that Guzma would have been preferred over Boss.