A creature that enters attacking never attacked, and cannot trigger any "attacks" triggers. To attack with a creature means to DECLARE it as attacker in the declate attackers turn based action. The rules spell this out explicitly:

508.3a An ability that reads “Whenever [a creature] attacks, . . .” triggers if that creature is declared
as an attacker. Similarly, “Whenever [a creature] attacks [a player, planeswalker, or battle], . . .”
triggers if that creature is declared as an attacker attacking that player or permanent. Such
abilities won’t trigger if a creature is put onto the battlefield attacking.

508.4. If a creature is put onto the battlefield attacking, its controller chooses which defending player,
planeswalker a defending player controls, or battle a defending player protects it’s attacking as it
enters the battlefield (unless the effect that put it onto the battlefield specifies what it’s attacking).
Similarly, if an effect states that a creature is attacking, its controller chooses which defending
player, planeswalker a defending player controls, or battle a defending player protects it’s attacking
(unless the effect has already specified). Such creatures are “attacking” but, for the purposes of
trigger events and effects, they never “attacked.” They remain attacking creatures until they’re
removed from combat or the combat phase ends, whichever comes first.