Thanks to The Word of Gostev I'm now running 9.5u4. Just in time to offload backups from our almost saturated archive server.
The setup was a walk in the park, but now I'm left with some interrogations, I'm sure you can help me with that

Time window to upload to object storage
I have defined a time windows that permit upload from 21:00 to 05:59.
I see the job start at 21:00 and stops with a failed status at 05:59.
At the next start, it doesn't seem to continue from where it has stopped. Is it just an impression or the way it is supposed to work?
Upload Throttling
Rather than a time window to upload I would prefer a throttling during business hours. Is it achievable with a Network Traffic Rule? If yes which IPs should I put in the range?
Thanks for your help,
Cédric