Stuck at "receiving data" when connecting to linux servers.

I figured i’d post this here since i’m running out of ideas.

I’ve been trying to figure out what was going on for about a week now and pretty much pinpointed it to being a problem on my home network, or my steam account (unlikely)

Observed behavior:
-Official servers: OK
-Community/Modded servers: OK
-Connecting to my linux rust server: Stuck at receiving data.
-Connecting to my friend’s linux rust server: Stuck at receiving data.
-Connecting to my friend’s windows rust server: OK.
-My friend connecting to my linux rust server: OK.

My main computer is on windows 10, same behavior observed also on my linux laptop (same home network).

Structure of my home network, if it can help:

Internet <-> DSL modem/router (set to forward all) <-> linux router <-> everything else (laptop, desktop, etc…)

I would love to avoid the whole router+router, but i don’t really have a choice, this modem can be set to bridge, but if i do that i lose the phone line it provides, so that’s not an option. Also configuring it is a telnet based nightmare so setting it to forward all is as far as i’ll go with it.

I tried to reinstall the game, several times.
I tried to reinstall the server several times.
I tried removing my settings several times too.

Right now I’m out of ideas.