CMF1_hacker already deleted the dynamic island app. And tried to restore developer settings. It continues to happen. Hopefully it’s fixed in the next update.
As far as battery drain, i don’t know what else to do. I notice it happens with WhatsApp, and gaming apps like Clash Royale. Although CR is a gaming app so i get the battery usage, but WhatsApp is another messaging app so i don’t understand that behaviour.