To find the graded value, you can research sold prices (safer bet then looking at current, for-sale listings) on eBay, Heritage Auctions, PWCC, or Goldin Actions
2 Mewtwo & Mew-GX Mewtwo & Mew-GX features in Pokemon : Price : $140 USD / 117 GBP / 137 EUR / $182 CAD Card Number / Rarity: 242/236 / Secret Rare Set : Unified Minds HP: 270 Ability: Perfection This Pokmon can use the attacks of any Pokmon-GX or Pokmon-EX on your Bench or in your discard pile
If at least one of the represented creatures is wearing a hat, the creature has menace
The most expensive card from the Scarlet and Violet series is Umbreon ex Illustration Rare from Prismatic Evolutions , with a market price of $1,011.07
There might be better engines to power it up and maybe find ways to get it back, but the card seems powerful
Things are also more interesting when you have spells like Change the Equation and Anoint with Affliction seeing play in Dimir and Azorious Control