4 official rulings from Bandai, last ruled Sep 6, 2024. Straight answers to how this card actually resolves.

When exactly is the timing when this card's <Trash> <All Turns> effect triggers?
It triggers at the timing when this card is in the trash and your [Dorugamon] would be deleted. <Trash> means that an effect can trigger and activate when the card is in the trash.
Ruled Sep 6, 2024
If I use this card's <Trash> effect to digivolve when my [Dorugamon] would be deleted by its DP becoming 0, can I prevent that deletion?
Yes, you can. However, the DP-reducing effect will be carried over after the <Trash> effect activates and digivolution occurs, therefore deletion will occur again if the DP is still 0 after the effect activates and digivolution occurs.
Ruled Sep 6, 2024
I used this card's <Trash> effect to digivolve when my [Dorugamon] would be deleted due to its DP being reduced by 10000. Its DP became 0 due to the DP-reducing effect, but can I activate this card's <When Digivolving> effect after it digivolves at such times?
No, you can't activate it. The Digimon is deleted before the <When Digivolving> effect activates.
Ruled Sep 6, 2024
Does "delete 1 of your opponent's Digimon with a play cost of 4 or less instead" in this card's <When Digivolving> effect activate instead of "Trash 1 card in your hand. Then, <Draw 1>"?
No, it activates instead of "Then, <Draw 1>."
Ruled Sep 6, 2024
Got a line that uses DexDorugamon? Map it in the builder and share it with a link.
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.