Just an observation… Mainline Protestant churches have been falling all over themselves to be relevant for decades and nothing has arrested the numerical decline in the number of adherents. They have: allowed clergy to marry, women to be ordained as deacons and later priests, allowed no-fault divorce and many have blessed same-sex marriages. They have lowered the bar for admission to their churches and the pews are emptying. Nothing trendy is bringing people back.
So I attend a RC service on the weekend (I normally worship at an Anglican church) and the numbers are impressive. The service is in French and the church is 75% full - on Canada Day weekend no less. The RC’s have remained steadfast in their doctrine, and people still come. I’m not suggesting that church attendance is not declining in the RC church - because it is. But they are not trying to lure people back to church with changes to doctrine what whatever might be hip and cool right now.
My chief observation is that Mainline Protestant churches here in Canada have gone out of their way to apologize to every group they may have offended over the course of history, they have watered down their teaching so it is not offensive to anyone, they have embraced inclusive language, removed any expectation of weekly attendance and, essentially, preach a doctrine that God loves everyone as they are and without expectation that they change. And the end result… no one cares.