Unfortunately before I started looking into whether this is possible, my tv auto updated to 1220.6, so it looks like I can't root.
That said, does anyone know how to do this, or point me in the right direction?
So you need to wait new root or buy new TV with old rootable firmware or somehow downgrade (reprogram eMMC flash memory) to older firmware.
Yes, you need to have TV with rootable firmware and you need to write your own interface or make some binary patches to the existing one, which add new functionality. Stuff in built-in eMMC flash memory is signed, so you can't simply overwrite executable files which implement old interface to new. You need to kill processes which doing old UI and load new after TV rooted. Or patch old UI processes at runtime (root is mandatory anyway).