If I use Lumineon V's "Aqua Return" attack against a Defending Pokemon with a Handheld Fan attached, does the Handheld Fan move an Energy from Lumineon V to one of my Benched Pokemon or does the Energy get shuffled into the deck due to "Aqua Return"?

Aqua Return puts Lumineon V into the deck as part of its attack before the Energy can be moved for Handheld Fan's effect. The order of operations is that effects of the Pokemon's attack happen first, and then any triggered effects on the Defending Pokemon happen next.

Relevant cards

SWSH9_40

SV6_150