After looking into this more, most of this content is already covered in:

• https://wikitech.wikimedia.org/wiki/Metrics_Platform (intro)
• https://wikitech.wikimedia.org/wiki/Metrics_Platform#About
• https://wikitech.wikimedia.org/wiki/Metrics_Platform/FAQ

I've updated these sources to consolidate the information and remove references to the monoschema. I've also moved the content from Template:Metrics_Platform/Docs/Content/Instrument_Overview into the FAQ.

The ideal organization for this content would be a narrative description (not structured into an FAQ) that provides a definitive list of the currently available capabilities of the Metrics Platform. However, because many aspects of the Metrics Platform are still in flux, it would not be feasible or maintainable to create this content at this time. For now, let's continue using and updating the FAQ in its current format.

For these two remaining content pieces:

• Is the Metrics Platform the right tool for your needs?
  • This will be documented as part of T370363: Document when to use Event Platform vs Metrics Platform for instrumentation
• Definitions of key terms such as experiment and instrument
  • These will be added to https://meta.wikimedia.org/wiki/Research_and_Decision_Science/Data_glossary and can be linked to from the FAQ once they are live.