Hello @jdavidl12 and welcome to the forum!
‘No files were found at the remote location’ using Onedrive for business describes an infamous Microsoft limit at 5000 files that you might have hit. Feel free to run your own research, but at least the article above solved the issue by switching from OneDrive to OneDrive v2 (Duplicati types) to use the newer Microsoft Graph API. Specifically it looks like Microsoft OneDrive v2 (Microsoft Graph API) is what might help this…
… but if it doesn’t, then Db rebuild with rclone od4b doesn’t work is a success using Rclone storage type.
Duplicati.CommandLine.BackendTool.exe running a list operation (avoid any which may change things) would be one way to see what the actual backup is seeing. You might even carefully move the 5001st file elsewhere to see if the view improves, then move it back to avoid Duplicati missing it after bypassing the list view limit. You can get the Target URL for the command below from the job’s Commandline or Export.
C:\Program Files\Duplicati 2>Duplicati.CommandLine.BackendTool.exe help
Usage: <command> <protocol>://<username>:<password>@<path> [filename]
Example: LIST ftp://user:pass@server/folder
Supported backends: aftp,amzcd,azure,b2,box,cloudfiles,dropbox,file,ftp,googledrive,gcs,hubic,jottacloud,mega,msgroup,onedrive,onedrivev2,sharepoint,openstack,rclone,s3,od4b,mssp,sia,ssh,tahoe,webdav
Supported commands: GET PUT LIST DELETE CREATEFOLDER
C:\Program Files\Duplicati 2>
I’m not sure what shape the first stopped backup and subsequent repair left things in (got extra logs by any chance?), but a reasonable first step to try seems to make sure Duplicati can see all your destination files.