Thanks for your answer ! It was in fact linked to my 6th question… And IPV6
I got the same error with a docker pull which led me in a rabbit hole where I found that some services (including docker hub and hugging face hub) are using rate limit methods intended only for IPv4 and so, are de facto blocking / only checking the first half of IPv6 adresses so it is entire ranges that are blocked at a time…
So as a workaround I can just disable IPV6 in ubuntu /etc/sysctl.conf…