Myra’s activated ability targets only the instant or sorcery card in your graveyard. It doesn’t target the Attraction. You choose the Attraction as the ability is resolving.

Myra’s activated ability creates a delayed triggered ability that will trigger whenever you visit the chosen Attraction. This ability will continue to trigger as long as the Attraction is on the battlefield and the exiled card remains exiled, even if Myra leaves the battlefield, loses her abilities, or changes controllers. It will also continue to trigger if the Attraction somehow loses the midway counter.