If I could be God for a day apart from providing a cure for all diseases I would tell people that there's no need for religion. That nobody needs to be worshipped or appeased, that idea's part of humanities' childhood.
That there are no rules except treat other humans with knowledge, compassion and empathy. It's important to use your intelligence and your instincts together so stop ignoring feelings because they're part of your evolution.
Stop worrying about death and live now, to the fullest every day. There is no hell or punishment so just chill and enjoy life. That all bets are off so just wait and see.