I’ve been recently looking at why davx/accountmanager webdav mounts have 0 bytes file writes, and saw rclone wrappers work the best.
Rclone is very versatile and speaks Proton Drive too. So the advice goes for most storage services, from S3 / backblaze to murenas or any nextcloud webdav too:
- Round Sync - Rclone for Android | F-Droid - Free and Open Source Android App Repository (setup task/schedules for sync transfers + behaviour. Supported by seedvault too)
- GitHub - chenxiaolong/RSAF: An Android Storage Access Framework document provider for rclone (gives you the bare SAF mount - as in can be targeted by other Apps, I think Seedvault implicitly)