TrueNAS used to support OneDrive in the past, but it was removed due to relying on an out-of-date official Python library.
There aren’t any up-to-date libraries around. We are not opposed to having this feature but it must be maintainable/supportable without much burden.
If someone is able to point how to achieve the same through pure rclone CLI or some GraphQL code we will consider adding it back.