4 official rulings from Bandai, last ruled Sep 13, 2024. Straight answers to how this card actually resolves.

What does an "add X000 to the maximum your DP-based deletion effects can delete" effect do?
Such effects increase the maximum value shown for DP-based deletion effects. For example, while "<Your Turn> Add 1000 to the maximum your DP-based deletion effects can delete" is activated, "<When Digivolving> Delete 1 of your opponent's Digimon with 3000 DP or less" will allow you to delete an opponent's Digimon with 4000 DP or less.
Ruled Sep 13, 2024
If "add X000 to the maximum your DP-based deletion effects can delete" is activating, can the maximum be increased for an effect such as "delete 1 of your opponent's Digimon with DP less than or equal to this Digimon's DP" that references a Digimon's DP for deletion?
No, it can't be increased. You can't increase the maximum of a DP-based deletion effect that doesn't show a numerical value.
Ruled Sep 13, 2024
Is this card’s <When Attacking> “Choose any number of your opponent's Digimon whose total DP adds up to 6000 or less and delete them” effect also affected by its “add 2000 to the maximum DP you can choose with DP-based deletion effects” effect?
Yes, it is. If you have a red Tamer in play, you can choose any number of your opponent's Digimon whose total DP adds up to 8000 or less.
Ruled Sep 13, 2024
Does this card's “add 2000 to the maximum DP you can choose with DP-based deletion effects” effect also raise the maximum DP I can choose with other deletion effects besides those on this card?
Yes, that's correct.
Ruled Sep 13, 2024
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Questions and answers are Bandai's official rulings, collected and translated by the DigimonCardGame Wiki community and reused here under CC BY-SA. Card names and card text are © their respective publishers; Combalo is not affiliated with Bandai.