R6350 - DoubleNAT, Strict NAT, No IPv6

Just from the title, I have it pretty down bad; here's my situation:

• My internet service (no modem) is provided through my apartment building / apart of my lease
  • The ISP is UNITI (https://uniti.com/) and I connect my router to the ethernet port in the wall and it provides my router internet. Basically... the port in my wall is my modem. 
• On my Xbox Series X, I am getting:
  • DoubleNAT
  • Strict NAT
  • Only using IPv4, IPv6 apparently isn't available

 Here are the "things" I have done in effort to try to fix this using self-service options all over the internet:

• Factory Reset the router
• Internet Setup Settings
  • Changed Internet IP Address to Use Static IP Address
  • Changed Router MAC Address to Use This MAC Address and Use Computer MAC Address 
• WAN Setup
  • NAT Filtering set to Secured and back to Open 
  • Disable SIP ALG (current setting)
  • Disable IGMP Proxying and back On
  • Set my Xbox as Default DMZ Server and back off
• LAN Setup
  • Use Router as DHCP Server turned off and back On
• Turned UPnP off and back On
• Put all of the Ports required to be Open in Port Forwarding (https://support.xbox.com/en-US/help/hardware-network/connect-network/network-ports-used-xbox-live)

I HAVE NOT attempted to use Wireless Access Point or Bridge Mode; wanted to post this before I go through those as I did research and it's not always the best thing to do especially if I don't have another router. Unless someone can educate me a little better on this. 

Current IPv6 Settings:

• Auto Detected: 6To4 Tunnel
• Remote 6to4 Relay Router: Auto
• LAN Setup: 
  • Changed from Use DHCP Server to Auto Config and back to Use DHCP Server

Believe it or not, I am at a complete roadblock. Your help with this is greatly appreciated. 

Also, if this helps some of you I came across this site that tests my IPv6 that is safe to share: