Teamspaces (Notion)

https://www.notion.so/help/guides/teamspaces-give-teams-home-for-important-work:

With teamspaces, you can organize your entire company in one place, while giving
each individual team their own space to organize docs & projects. Everyone has
easy access to all the information that’s relevant to their work, and can
customize the Notion sidebar to reflect their role and priorities.

The image on that same page seems helpful:

• A section for the company-as-a-whole
• A section for Sales
• A section for Marketing
• Etc.

Maybe this could even be used for having one Trello workspace that covers both private & business?