We don’t need a core dev to own the device but there needs to be an active community member capable of supporting the device, yes.
Also, these devices are “supported” because they run a close-to mainline kernel, where Android and Ubuntu Touch use almost exclusively (and Android exclusively) outdated downstream kernels. With close-to mainline we mean a recent kernel version (e.g. 5.11.7 for multiple devices in that list) with just a few out of tree patches.
We don’t need a core dev to own the device but there needs to be an active community member capable of supporting the device, yes.
Also, these devices are “supported” because they run a close-to mainline kernel, where Android and Ubuntu Touch use almost exclusively (and Android exclusively) outdated downstream kernels. With close-to mainline we mean a recent kernel version (e.g. 5.11.7 for multiple devices in that list) with just a few out of tree patches.