Moca with XD4 modem (X-2gig)

We recently upgraded to X-2Gig service and received an XD4 modem (which i understand is a DOCSIS 4.0 modem), and while the service works great fat first, at full speed, it drops to half speed after a few hours.  This speed drop does not happen with our MoCA adapters unplugged, so I suspect some interference with MoCA.

Does anyone have any guidance on getting the XD4 to work well with Moca?  I am a little lost trying to figure out which frequencies are used for X-2Gig, what the XD4 uses, what sort of splitters to buy, and how to configure MoCA for it all to play nicely.  Thanks.