I agree that it's no way to live.
This cliche phrase definitely takes me back!
The problem here is of course that gods aren't capable of solving this kind of problem anyway; an external, instrumental purpose ('God made me to do X', or 'God created me to have Y effect on the world') isn't meaningful in the way people want intrinsic or subjective purposes to be anyway.
In that sense religious institutions provide the same kind of earthly, banal, limited meaning that hackerspaces or secular charities or sports clubs or families do. But they're not any better at making existentialist yearnings well-formed than anything else is.
I also don't think all that is necessary to explain the phenomenon at hand. That account is way too broad.
Imo the drive here is more narrative; it's about making the stories of our lives make sense— often in the simple sense of making them unsurprising. Discovering a diagnosis can be very cathartic, and can (partially) explain lots of patterns and events from one's past. It also brings some relief because it tells us that we are not uniquely defective in our failings and points us towards examples of others who have managed to succeed or survive despite the same ailment. And it gives us a vocabulary for identifying similar people from whom we can learn and in whom we can find solidarity. All of those things being are rewarding and/or useful.
as someone who has a bunch of adult friends getting autism or add/adhd diagnosed, there is an immediate phase of “all of my problems are caused by this”, followed by “how do i cope with this”, and finally “this is just helpful context for me”.
there are quite a few that get stuck on one of those phases, but largely most people loop back around to a more reasonable view.
Different sides of the same coin.
I'm not religious btw, this is just what I see.
Calling it "a hole" even, is stretching the metaphor too far. People have needs, and religion has often been used to fill that need, as has nationalism, and occupations, and any other thing. But there isn't a single "hole", and that hole doesn't have a "shape". There's just people who have needs, and ways people have tried to fulfill those needs.
A person can choose their religion now, they can label themselves according to what they believe in. For many in the West religion is a kind of loose political or ideological club. For many, religion and identity is found and chosen from within. "it's the real me", "I have found the meaning in my life by this chosen identity".
But it has not been this way forever, and in other (non-Western) parts of the world it's still another way.
The other way is to have your identity defined from above or outside you. For most people who we were, our identities were defined according to our position, where we lived, what our father did, what the culture was. Your father named you. To be "real" you would behave according to what identity had been given to you. Ultimately God is above everything and with regard to identities, symbolically represents this top down giving of a meaning of life.
I guess it's making the hole bigger than trying to fill it with something else.
Edits:
a) I suppose that some older religious people who were "born into it" might be more towards identity-from-outside.
b) It would work with non religious people in identity-from-outside cultures. Stereotypical examples: a farmer in rural China, a salaryman in Japan or a peasant in 17th Century Germany. Or a culture where children are encouraged to "do their best" with what they have at hand vs "find themselves" with things they might discover.