Can I use XD4 with my own wifi router?

If I upgrade from the asymmetric plan to X-500 or X-Gig, I understand that I'll be getting XD4 modem (DOCSIS 4.0) + XB8 gateway.

I recall XD4 has two 10G ports, so in theory I could connect my own router (ASUS or Netgear with some advanced VPN setup), and ignore XB8 completely, maybe even just disconnect XB8, right?

Is there any need in using XB8, if I am not planning to connect via it?