Google Analytics 4 Now Offer Ability To Import Offline Events
https://support.google.comYou can import offline events from sources that don’t have an internet connection or that otherwise cannot support real-time event collection via the SDKs or Measurement Protocol. Once you upload events, they are processed and use the timestamp you provide or the timestamp of the upload if you don’t provide your own.
Removing this data requires either a data-deletion request or user deletion.
There are some limitations like event names must be 40 characters or fewer, may only contain alpha-numeric characters and underscores, and must start with an alphabetic character, etc