Not all religions are centered around the existence of a god though. A religion can be centered around any ideology, you only have to treat it as sacrosanct.
I'm not so sure, I think people are actually filling it with lots of other ideological stuff. Wokeism is one example, but Trumpism is kind of another? Similarly a lot of crypto people treat it almost religiously.
People like to have some sort of tribal affiliation and it tends to be around some sort of ideology or at least gestures towards one. I think this is often harmful, but a lot of this stuff is related to an underlying human truth.
People are not replacing god with cancelling people on Twitter. Those things are completely unrelated.