I've put this under the time series category since that's where it's most applicable, but it's really a data model / BSON issue.
The topic of higher resolution timestamps have been surfaced from time to time for at least a decade (https://jira.mongodb.org/browse/SERVER-1460), and usually prompts a response like "just use integers". With the addition of time series collections however, where the concept of time is integral to database functionality, I think it's time to reconsider adding a type with at least nanosecond precision timestamp support. Date's millisecond resolution is woefully inadequate for a number of relevant use cases, be it sensor data, financial data, log data, etc.