Full demo showing the source code and install process for Global Navigation bar across multiple site collections. Provide end users with facility to update central navigation with consistent display across many SharePoint site collections. Screenshots below with demo and full source code. Cheers.

- Supports both Classic JS and Modern SPFx site templates
- Supports SharePoint 2019+ with SPFx 1.4.1
- Supports SharePoint Online (SPO)
GitHub Repo
Video
Screenshot

References
https://github.com/tom-daly/spfx-global-navigation
https://github.com/dcashpeterson/Public-Samples/tree/master/Code/GlobalNavSPFx/SPFx