I’ve jumped through a lot of hoops and I’m not sure what steps were actually necessary but I’ll try to list everything I did. I do know ultimately what solved this for me, but I’m just not sure if the prior steps were necessary for the final thing to be effective…so yeah, thanks M$.
First off I made sure my Windows Firewall is On(even though I use Norton Security); you’ll have to go through the Windows Defender to turn it on. I set my router(Eero) to Bridge mode and connect it via ethernet cable to my modem/router(Spectrum ISP supplied POS)(I use the second router bc it has better penetration throughout the house). I port forward UDP 88, 500, 3544, 4500 TCP 80 and TCP & UDP 3074, 53 to my PC(my XBOX One works perfectly fine w/o doing anything). Read that on one of the other 10,000 posts about Teredo…dunno if they matter or not.
Then I went into Windows PowerShell(Administrator):
netsh int teredo set state clientport=88
netsh int teredo set state type=nataware (I was also able to use ‘enterpriseclient’ in place of ‘nataware’ here…didnt seem to make a difference but I dunno what the actual difference is…
and the one that fixed it all
netsh int teredo set state servername=teredo.trex.fi
So this connects to a teredo server in Finland (http://www.trex.fi/service/teredo.htm)
If you right click the Windows button, go to Settings>Gaming>XBOX Networking and check your status there you should at least have a connection and at worst you should have ‘Moderate’ NAT Type(you can also check this on the XBOX app for PC). If you then click ‘Fix It’ Windows will change your netsh Server Name off of teredo.trex.fi and back to the default of ‘win1711.ipv6.microsoft.com’ and you’ll be unable to connect or at best your NAT will be ‘Strict’ which for gaming amounts to the same thing(you won’t have voice chat and you won’t be able to connect to any game servers though you’ll still connect to XBOX Live).
So I dont know if that means M$'s teredo server is down or what but I know the default doesnt work for me. Also, even after several reboots, my Server Name has stayed on the trex.fi So hopefully this isnt something we’ll have to do after every reboot(though I’m sure I’ll have to do it again at some point).
I don’t know anything about networking or programming so I can’t really answer any questions; this is all just trial and error and consolidating what I’ve read elsewhere. Good luck