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

If I reveal a Digimon card with the [Legend-Arms] and a play cost of 7 or less with this card's <When Attacking> effect, can I choose to not play that card?
Yes, "You may play" means you can choose to play it or not. If you don't play it, return it to the bottom of the deck with the rest of the cards.
Ruled Mar 28, 2024
If there's a [BT9-047]/[Pomumon] and I reveal a Digimon card with the [Legend-Arms] and a play cost of 7 or less with this card's <When Attacking> effect, what happens to that card?
It can't be played due to [BT9-Pomumon]'s effect, so return it to the bottom of the deck with the rest of the cards.
Ruled Mar 28, 2024
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