Request for Customer-Owned and Managed router (COAM) on Xfinity Fiber (EPON)

I have Xfinity Fiber (EPON) to my house, terminating at a Comcast Nokia ONU. My account still has a leased XB7 gateway, and I'd like to switch to the member-owned router option described here:
https://www.xfinity.com/support/articles/member-owned-router-fiber-internet

I am NOT trying to use my own modem. I just want the ONU to hand off directly to my own router over Ethernet. My plan is 2 Gbps symmetrical, but the XB7's single 2.5 Gbps port has to be used for the ONU uplink, which leaves only 1 Gbps ports for my router, so I get about half the speed I pay for.

What's happened so far:

• About 2.5 hours on the phone across two calls
• My router's MAC was provided and a file was pushed to the ONU (supposedly)
• I received a "your service should be restored" text

Nothing has changed. The ONU still sends an 802.1X authentication request about once per second and never answers my router's DHCP requests. I power-cycled the ONU several times and it came back exactly the same, so it is still on the leased-gateway profile.

What I understand is needed (from another thread here):

1. Add the member-owned / customer-owned router (COAM) configuration to my account.
2. Replace the XB7 in my equipment inventory with my own router, in whatever order your systems require.
3. Push the updated provisioning/boot file to the ONU so it hands DHCP directly to my router without gateway authentication.

The same request was resolved here: https://forums.xfinity.com/conversations/customer-service/request-for-customer-owned-and-managed-router-coam/6af12521ae64e510d5bfc27c

Could someone please help? I'm happy to send my account details by direct message.