After reading the background discussion
Everyone is invited to participate in the Purism router poll who hasn’t done so already:
I notice that the OpenWRT One (thanks @j_s) not only supports 2.5 Gbps Ethernet, but can power itself off of it. That could allow one to leave the power adapter at home, potentially. It (or one of its premium derivatives) strikes me as an ideal reference board upon which a putative Purism Router would be built. Not to mention the legal advantages of copyleft licensing.