I would like to see official support for Filen. Filen is a very popular cloud storage service and supports rclone. I would like to see it added as an option for the S3Drive app.
We would happily include support for Filen as long as it ends up being merged to mainline release, currently it's still in open beta.
Support for Filen may be included in v1.72 release: https://github.com/rclone/rclone/milestone/60 which is planned to be delivered by November 21, 2025.