A surface level, the rarities determine how likely you are to find a card overall
When Pokmon-ex last left the format around five years ago, it was only fully evolved or Mega Evolved Pokmon that got EX cards, meaning they were mostly used for absolute powerhouse attacking and defending capabilities
The first steps of every new player in Pokemon TCG Live are very hard, and its because there are only a few cards and decks to play with
Again, these events last two weeks each
Realmwalker - Casting cards from the top of your library is always great for card advantage
Instead of doing a deep dive on Tiamat (look at the Ur-Dragon page, its the same deck) or even Xanathar (everyone is bafflingly building a mill deck, I guess to optimize what one card you get?), I think Im going to do a real shallow strafing run through everything to get the big hits out of the way first