Onboarding with many user profile fields – lengthy and detailed vs. short and essential?

So if you can imagine a dating app, the essentials are stuff like: gender, location, age, name, a photo

Then say you have some optional fields that are pretty useful such as "looking for" - their purpose for using the app.

And then say you have 20 other fields which are nice to have, but not need to have: religion, politics, languages, diet, relationship type/status, etc.

If you make the user fill them out during onboarding, well then onboarding gets kinda long and becomes a pain. If you keep it short with the just the essentials, then you end up with many minimal profiles e.g. people who just uploaded a photo, didn't fill out their bio, and left it at that.

What do you suggest?