Access to Thread border router's IPv6 from LAN

Hi, I’m using a Sonoff dongle E as Thread border router using the Home Assistant OS in a VM and Silicon Labs Multiprotocol add-on. But now I want to export it’s IPv6 subnet to the LAN of the hypervisor. Therefore I need a solution like NPTv6 to translate the plugins IPv6 through the VM to the hypervisor (using double translation/mapping). Could someone be so kind to create that? It could also be done using NAT66 (yes, there is such a thing):

Best would also be for the plugin to learn the local link address using a DHCPv6 request on the (hypervisor) LAN