How can I get my Xbox to pick up IPv6 when my router has it enabled?

I don't think the release and renew option is going to work. Due to if you use one of the two options. Is going to affect only to the IPv4 on the console

I should have mentioned in the original, I do use a wired connection.

I disconnected the Ethernet cable and connected wirelessly, then went back to wired. No change.

I did the power cycle with both the Xbox and router, no change. I'm afraid those did not work,

Do you not have the possibility to aks them a different router brand?

Are you able to see the Xbox in your router settings, right?
Are you able to assign an static IPv6 address to the console? (In some cases you need to ask to the ISP a valid static address, putting a random usually does not work)

I talked with Spectrum, my ISP, and they said they cannot touch it since it's not a router sent by them.

Other developments I've stumbled across are:

• Under the router's IPv6 settings, 6rd Tunnel is disabled and the option to change that is greyed out.
  
• Under Diagnostics, and under Internet Address, there are two rows. One lists IPv4 and its address and the other lists IPv6 and the address part is blank. Next to both of these is an option to Release and Renew. I've read a little about this but am a little cautious, so I wanted to know what you thought about that.
  

I greatly appreciated the effort you've put in to helping me so far.

I've tried the first option, clearing the MAC, and that didn't seem to work.

I have noticed a change though. In my router settings, where it shows what all is connected, it now shows all my devices under IPv6 address as well as IPv4 addresses. Until now, it only showed the IPv4 addresses. My Xbox however still continues to use the IPv4 address. Maybe this is something to work with? I will keep trying things.