There are many logging ways. For this, the server log is probably more useful than the job log, and it can be viewed live in a different browser tab. Profiling level gets quite wordy. See Viewing the Duplicati Server Logs.
Logging to a file is also a good plan. It’s a better permanent record, and has added settings and capabilities.
C:\Program Files\Duplicati 2>duplicati.commandline.exe help logging
Duplicati provides information for debugging and logging purposes. By default,
all debugging and logging is turned off.
Error messages are more verbose.
If something needs to be retried (e.g. upload failed) this will cause an
entry in the log file.
--log-file = <path>
The path to the log file e.g. "D:\duplicati\log.txt".
--log-file-log-level = Profiling | Verbose | Information | Warning | Error
Specifies the log level to use for the log file.
--console-log-level = Profiling | Verbose | Information | Warning | Error
Specifies the log level to use for the console log.
New log system with filters describes this new system’s advancements compared to the old (e.g. 126.96.36.199 beta).
For a detailed view of the Duplicati file requests to Windows, you can use Sysinternals Process Monitor, and filter to see only the Duplicati.Server.exe process. Its Windows-level work would likely mean more to Stablebit.
EDIT: Process Monitor not Process Explorer.