NextCloud File Shares: Private Files & Group Files

NextCloud: 15.0.6
Linux (Virtual) Debian Server

The Goal:
I would like to selectively share my (previously) private files to my extended family, but limit access to the parts of my NextCloud that are appropriate for each family member.

Additionally, I would like for them to be able to privately store their own files and folders, also sharing them with the family should they choose to.

What I have done so far:
Bought a domain name and secured it with SSL certificates, enabled strict https and ssl rules, closed/blocked all non-applicable ports.

I have working access from my LAN and WAN

What I need:
Help with configuring the shared folders so that my wife & daughter can see the entire shared music library for example, but the rest (or groups) of my family can only see & access files that are shared with them.

Help understanding the config structure, apps needed (and not) would be greatly appreciated; I am not a technical noob, but the interworkings of these pieces (or lack of interworkings?) have me scratching my head.

Each User:
    Private Folders: 
    Group Shared Folders:
        /Shared With Me/Documents
        /Shared With Me/Music
        /Shared With Me/Pictures
        /Shared With Me/Videos

Apps available:
Group Folders
Collaborative Tags
Everyone Group
File Access Control
File Sharing

If anyone can also explain how I would go about setting up a network share drive on my Windows 10 and Linux computers that would be awesome, tried WebDAV and had lots of problems, and gave up.

Using the NextCloud sync client is also not ideal (unless there is a list only option) as I have stored my entire cd collection and all my linux iso downloads in NextCloud and don’t want them synced to every computer.