TNG took a couple seasons to develop its identity and not just be more of TOS with new actors, and random gods, including Apollo, showing up is something that happened pretty regularly in TOS. The various gods in TOS are ultimately depicted as probably not being real gods and just being aliens with very advanced tech and maybe some weird biology, and there’s some indication that the Q are the same. Like the Prophets, they’re from a not-fully-corporeal reality adjacent to our own, and they have seemingly magical technology that we’re able to use; the Orbs from the Prophets, the Q weapons from the Q.
TNG took a couple seasons to develop its identity and not just be more of TOS with new actors, and random gods, including Apollo, showing up is something that happened pretty regularly in TOS. The various gods in TOS are ultimately depicted as probably not being real gods and just being aliens with very advanced tech and maybe some weird biology, and there’s some indication that the Q are the same. Like the Prophets, they’re from a not-fully-corporeal reality adjacent to our own, and they have seemingly magical technology that we’re able to use; the Orbs from the Prophets, the Q weapons from the Q.