We use NC in our church. We have a separate register for members with data on name, familyname, birthdate, sex, post adress, phonenumber, e-mail-adress, date when becoming member, name of previous church, date when left church, moved to another church, photo, etc.
I would like to integrate this register in NC. I think contacs app could be used with some adaption. It should not import new contacts automatically. It does not need all the CSS-fields but need other fields. I understand that the Notes-field can be used partly, and have also received some instructions to improve the UI and get rid of the CSS-fields here (Possibility to hide the detailed name to make a leaner UI · Issue #1101 · nextcloud/contacts · GitHub)
What I propose is a new app for this purpose, but think it could be based on Contacts-app.
Or are there other alternatives that I may have missed