2 official rulings from Bandai, last ruled Mar 28, 2024. Straight answers to how this card actually resolves.

This Digimon attacked the opponent player and was blocked by an opponent's Digimon that has more DP than this Digimon. Can I use this card's effect to digivolve into a level 6 Digimon card with [Leomon] in my hand, ignoring its digivolution requirements?
No, you can't. This card's <When Attacking> effect is an effect that activates before your opponent blocks, therefore the activation timing has already passed by the time of the block timing.
Ruled Mar 28, 2024
This Digimon gained <Rush>, it attacked the opponent player, and I used the <Rush> effect to switch the target of attack to an opponent's Digimon with higher DP than this Digimon. In such cases, can this card's <When Attacking> effect digivolve into a level 6 Digimon card with [Leomon] in my hand?
No, it can't. Only when this Digimon attacked a Digimon with higher DP at the time of the attack declaration can this card's <When Attacking> effect digivolve into a level 6 Digimon card with [Leomon] in your hand, ignoring its digivolution requirements.
Ruled Mar 28, 2024
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