The Pokémon TCG Live game client will be offline for maintenance from 15:00 ~ 23:00 (UTC) on April 23, 2025 while an update is being applied. Please see the Version 1.25.0 - Patch Notes announcement for the full details.
Primary Deck

How can I change or delete my primary deck?
Answers
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Jokes aside, there is no primary or secondary deck. There is just grid with every decks you have available, of which you set one as "active" to play with, and the grid can be rearranged in order of which one you have played last time, followed by those you played before (RECENTS), you can also click on the star on the left top corner of each deck to always display them above other decks in (FAVORITES) tab, or set to display (ALL) which will display all decks in alphabetical order.
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Well… You never mentioned you play PTCGL on smartphone. My bad that I keep forgetting about it's existence. 😉
The user interface in mobile version of the game is however not that much different, and it appears that you have already figured out that some sections have to be opened separately by tapping on sub-menu button.
From my understanding, your issue is that you are trying to delete your active deck selected to play with. (The one with white checkmark in colorful hexagon in top right corner. (Red one in case of standard format.))
You have to select different deck, tap on the "SET ACTIVE" button which would return you back to main screen, then tap on "DECKS" button again, select the deck you want to delete, tap the "kebab" menu button and you should be able to delete the unwanted deck.
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