Is insomnia a symptom of sleep apnea?

Yes: Yes, it is a prominent symptom.

YES: Insomnia is most often thought of as both a sign and a symptom that can accompany several sleep, medical, and psychiatric disorders characterized by a persistent difficulty falling asleep and/or staying asleep or sleep of poor quality.

Could be.: They may be independent of each other. Sleep apnea can certainly lead to insomnia due disturbed sleep.