quick update:

i learned that sf6 uses the following ports:
Street Fighter 6 on PlayStation 4

TCP: 3478, 3479, 3480
UDP: 3074, 3478, 3479

Street Fighter 6 on PlayStation 5

TCP: 3478, 3479, 3480
UDP: 3074, 3478, 3479

Street Fighter 6 on Xbox Series X

TCP: 3074
UDP: 88, 500, 3074, 3544, 4500

Street Fighter 6 on Steam

TCP: 27015, 27036
UDP: 27015, 27031-27033, 27034-27036

i doubt that anything other than the ports listed under steam should actualls concern me,
but the low port numbers 80 &500 seemed like potential snags

i tried the following things:

i added net.ipv4.ip_unprivileged_port_start=0 to
/etc/sysctl.conf

i added entries for the ports 0-1024 for tcp & udp to my firewall.

these things did not help.

i also tried to set up port forwarding,
where i found out that it would not let me set external ports outside of the range 8044-8063.

i assumed that my provider might be doin weird stuff that was causing the issue.

but if that was actually the case,
why would the windows version work?

resolved

i found the following guide on reddit:

Bro just disable ipv6

i followed the instructions and it worked