Are the typical Synology, Qnap, or TrueNAS devices with default Linux, macOS and Windows clients going to be set up correctly by default? If any of the typical things someone is likely to setup following wizards in a home or small office is likely to result in lock not working correctly for SQLite, then it is fair for them to warn against using it on a network file system.

As an application format, you don't generally expect people to be editing an ODF file at the same time though, so network locking doesn't really disqualify it for use as a document format.