I have been experiencing extremely slow tumbleweed updates for a while now. A rough estimate based on counting how many seconds it takes to retrieve a RPM would put it somewhere < 10 KiB/s.
Every now and then providers send a questionnaire to ask if you are happy with the network and if there is something wrong, I complained about various things, then a technician called me, and I told him everything that was wrong, among the things that were wrong was the download of Opensuse updates, and I told him that I used a VPN to be able to do them… from the next day I no longer had to use the VPN because everything worked