It is certainly easier with a larger switcher. I'm also not sure whether I understand your layering and whether there are enough keys available...
But it may also work for you this way:
You can set the first output to Program
You send the Preview to the second output.
Now you can provide the lyrics layering on the program level.
In the next transition area you can compile the key for the preview level. If this layer is to be used as input for the first layer, then output two must be transferred back to a free input via HDMI.
