Need 4k boxes that work with my modem

Hello,

I have 1 DVR box (XG1v4) and 2 additional boxes (XiD). Those additional boxes do not offer 4k, so I would like to upgrade to boxes that are capable of handing 4k content.

I provide my own modem/router, so I cannot use the wireless boxes. Can I please have 2 additional 4k boxes that utilize coax connections?