Server list 650kB/s

while (true)
{
download_everything_whatever_I_filtered() ;
}

Well it's nice to see it drop that low today. It's a known issue and there are community made workarounds available, see this thread.

Install the Faster Server Browser using the PA Mod Manager (PAMM):
https://forums.uberent.com/threads/rel-pa-mod-manager-cross-platform.59992/

https://forums.uberent.com/threads/wip-faster-server-browser-mod.63947/

Add your vote to here: PA#4081

Done and done. Thanks.

Is this issue list the official one ?

Yes.

The other network issue grows over time as you encounter more users:
PA#4068

For that issue install the Optimise User Tag Map mod:
https://forums.uberent.com/threads/wip-optimise-user-tag-map-mod-to-improve-startup.63917/