It's just the Xbox One X (wired) that seems to be having these issues. The other Xbox One setup on wireless hasn't seen the Teredo issues and is on the same Insider program. I'll get off the super early Alpha updates on the Xbox One X I guess.
It's just frustrating jumping through all these hoops because I never saw this stuff with my old ASUS RT-N66U I had the last 5 years. I also have friends that have this router and they haven't had to go through this.
Thanks for the support. I want to figure this out.