I normally refer to this as a teams "operating agreement". Individual settings should be left to individuals. Normally a team operating agreement (formal or informal) includes:
1. Where will we collaborate? (SharePoint, Teams, other?)
2. How will we conduct our meetings? (Status reports, hot/blocked issues only, open round robin)
3. How will we make decisions? which also ties to...
4. Do we have a project/program/service Roles & Responsibilities document that everyone has seen and agreed to.
5. How will we ask for help or executive support?
These agreements are foundational to good operations. Once these are established you can create more details around meeting types (camera free or visually engaged) and the like. It is normally not at all successful to try to mandate for end users what to do with notifications or other individual settings. You will normally get a lot of dissatisfaction on that. It is however useful for individuals to use their Out of Office message more frequently to advise of off hours, time differences or vacations.
Service outage or customer facing notifications are a very different thing and I have not covered that here. I hope this is helpful!