What Duplicati version is this? There’s a bug in the current beta (fixed in canary and experimental) that might explain those dblock downloads. Empty source file can make Recreate download all dblock files fruitlessly with huge delay #3747. For hangs, do you have any sense of how well B2 is working for you?
Here is a sampling of errors I was having on B2, but it’s hard to know what’s B2, and what’s the network. Backup log will show you “RetryAttempts” in “BackendStatistics”. Retries can cover problems up to their limit which could be raised by –number-of-retries and –retry-delay to try to ride through troubled periods.
I haven’t tested it, but it might be possible to put a safety timer with –http-operation-timeout at something longer than your network will ever normally take to upload or download a remote volume (50 MB default).