Players can export their creations - before migrating accounts - as a text file within Pokmon TCG Online by navigating to the Deck Manager page and downloading a separate file for each deck
An early in-game tutorial does a somewhat decent job of giving you a crash course in the basics of a match, and subsequent single player campaigns help to build on this with piloting specific decks, but there is a considerable amount of extra knowledge you need to acquire before you can reasonably hope to stand a chance against real world foes
You wouldn't play this card for any one of these abilities, but being able to play one card that can Swiss Army Knife itself into just about anything you need at the moment, and at instant speed, means this should serious sideboard consideration

Attack!" When Kaiba activates the effect of that monster, he announces "B-Buster Drakes effect activates!" When Kaiba Summons "Battle Ox", he announces "Brace yourself for my Battle Ox!" Most of the time when Kaiba declares an attack with that monster, he announces "Go, Battle Ox!" followed by "Axe Slam Attack!" When Kaiba Summons "Blade Knight", he announces "Blade Knight!" Most of the time when Kaiba declares an attack with that monster, he announces "Slash em, Blade Knight!" followed by "Blade Attack!" When Kaiba Summons "Cave Dragon", he announces "Cave Dragon!" Most of the time when Kaiba declares an attack with that monster, he announces "Cave Dragon attacks!" When Kaiba Summons "Dictator of D.", he announces "Dictator of D.!" (spoken as "Dictator of Dragons!") Most of the time when Kaiba declares an attack with that monster, he announces "Dictator of D

Unbanning Jace, the Mind Sculptor and moving the Masters set focus away from Modern don't solve this problemnot by a long shotso expect bigger, more impactful changes in the next few years (like the creation of a Modern 2.0 / Fronter-like format)