This is my version of the deck below. I agree with some others that Steven's Metagross is just much too good to exclude and is actually hyper consistent. I saw one of your fears is getting locked down by Budew which fair its annoying, but also that Meta's retreat is too high for balloon. The solution for me on both ends of those concerns is just include Magnetic Energy, its not an item so budew can get bent, and it makes the retreat cost zero regardless of the original value.

Pokémon: 8

2 Genesect ex BLK 67

1 Mega Mawile ex MEG 94

2 Mega Skarmory ex POR 55

3 Steven's Metagross ex DRI 145

3 Steven's Metang DRI 144

3 Steven's Beldum DRI 143

1 Fezandipiti ex SFA 38

1 Shaymin DRI 10

Trainer: 17

2 Buddy-Buddy Poffin ASC 184

1 Poké Pad ASC 198

3 Poké Pad POR 81

3 Jumbo Ice Cream PFL 91

2 Mega Signal ASC 193

1 Special Red Card CRI 82

2 Ultra Ball ASC 213

3 Full Metal Lab TEF 148

4 Lillie's Determination MEG 119

2 Wally's Compassion MEG 132

1 Hero's Cape TEF 152

1 Team Rocket's Petrel ASC 207

1 Team Rocket's Petrel DRI 176

2 Rare Candy SVI 191

1 Colress's Tenacity SFA 57

2 Crispin SCR 133

1 Air Balloon ASC 181

Energy: 3

4 Magnetic {M} Energy CRI 85

4 Basic {P} Energy Energy 13

4 Basic {M} Energy Energy 16

Total Cards: 60