Please check the video description 
Thank you, @usefulvid, for making and sharing the video!
I’m sorry to hear you had such a poor QNap + Jota Cloud experience, hopefully things have improved since the video was made Duplicati 2.0.3.5 canary and there have been at least 4 releases since then (though the ones before 2.0.3.9 were even less stable than 2.0.3.5).
If you compare / review Duplicati again in the future, please consider trying the more stable beta branch if you find canary versions inadequate.
Which one would you suggest? Is the parallelism addressed and what about continue a stopped backup?
Stability is only one point. If backups/restores still need 5 days the chance of getting interrupted is very likely (even if its not duplicatis fault).
Some stability issues were introduced with the initial general (possibly not specific to Jota) parallelism support.
They are mostly addressed and we’re hoping the next canary version brings back the stability while keeping the parallel improvements.
Stopping / interrupting a backup shouldn’t cause any major issues as Duplicati will pick up where it left off with the last COMPETED upload.
Interrupted restores, however, are still not really “resumable”. 
Though to be honest, I’m not sure why route restore was going to take five days.
Stability wise, version 2.0.3.3 beta (the most recent beta for now) is the way to go, but I know it does not include some features that are already in the canary versions that people really like.
Just to be clear, I’m not disputing your experience - if that’s how things went for you that just means we’ve got some more goals to aim for at our end. 
@JonMikelV Thanks for the constructive feedback. Jottacloud is insanley slow with one stream and duplicati did not performed well on my qnap nas. This were the main reasons for the slow restore.
I thought resuming a backup is also not possible because I had no indication in the GUI about it.
This is another thing which I like to criticize: There should be a menu entry for process status. Actually I only have the info bar at the top. I like to have an overview about the last run processes and its status.