ES3.1 - How?

First screenshot shows the Preview when using ES3.1
Second image shows Preview when ES3.1 is turned off and Shader Model 5 is being used (default)

A Rect Light doesn’t seem to be supported at all. Even by cranking up the Light Intensity. The scene stays black.

Questions:
So are the regular lights for ES3.1 not supported?
How can you do your lighting when using ES3.1?

Thank you so much for any little hint, info and recommendation!
Appreciate that!