Second, Millennials want to DO something. They want to HELP someone, some group, some people. They actually want to DO what Jesus called (commanded) us to DO. So, if we don't want to lose Millennials forever, get busy. Stop arguing. Stop squaring off conservative vs progressive, literalist vs humanist vs inspiration, etc., etc., ad nausium. Stop engaging in endless, foolish public debates. Instead, look around, see what your community needs (ask them), make a quick plan to help (revise after each attempt), AND then invite Millennials to help. It's really not that hard.
It's that or head back to social media and natter on endlessly over one hot button issue or another, judging others in precisely the way we are called not to, ever. Let's trust God to deal with God's stuff and let's get busy with the loving (God and humanity) part.
Wishing you a blessed and busy day.