I have an Android Smart TV with locked bootloader, but enabled root access. It doesn't allow to remount /system as read/write-able, so I can not install something like Superuser, but there is a sudo app (no su binary, however).
In short, to access the device I need to turn on adb over Wifi (it does not have any USB ports) to debug my app.
Is it possible to do this over terminal?
You can try the process mentioned here since you have some sort of root access. However I'm not familiar with Android TV's so that may or may not work.
Also, you mentioned root access but no su binary and instead you have sudo? If you have any sort of escalated privileges you should be able to remount /system as read/write and install Superuser.