Games have different dynamic and strategic gameplay levels and have poor user onboarding and experience interfaces
A great way to build and edit your decks is directly within Pokemon TCG Live
If you really wanted to cover all the bases, you could add 9 more cards that, according to my research, are rarely but occasionally played competitively these days: Arrogant Wurm, Beetleback Chief, Bottle Gnomes, Fyndhorn Elves, Order of Leitbur, Order of the Ebon Hand, Portent, Shield Sphere, and Whispers of the Muse
Supporter cards are the best kind of cards in Pokemon, so being able to recycle them is a fantastic ability
Your first booster pack will have a fixed set of cards, with one of them being a rare ex card and another being a Kanto starter Pokemon
(Spoiler: I never drew it.) I ended up 4-3 and, in hindsight, this was probably not the best I could get out of my pool