Could you explain the collaborative work you do with Google Office? Does it have to use office file formats? Is it required to be web-based and accessible via a browser?
Could something like Obsidian.md work (with some live sync related plugin), where you write in markdown for various note-taking and documentation formats? Obsidian is proprietary, and I haven't used it myself, but I heard good things about it. It's also possible to configure vim and emacs with plugins to provide the same functionality as Obsidian.
I personally want to learn LaTeX for my office needs, and I believe there's ways to do live collaboration with various tools, but LaTeX is a rabbit hole and much more difficult to learn.
From what I read, NextCloud's office suite is based on LibreOffice/Collabora Office, so @Juice@hexbear.net's suggestion is probably your best solution if you can setup a server to share with your family and friends.