There is a standard way to do this, but it’s not in the lights group. The lights groups only let you turn ON when there is motion, not let you turn OFF when there is motion.
I’m quadriparetic, and I use motion sensors as touchless switches, so I’m very aware of what’s built into the official mobile app. (I can code, but I don’t want to: processing groovy with a text to voice reader is a real pain.)
Anyway, the standard option to turn something off after a motion sensor trigger is in hello home actions. But there is a trick to it. You have to also change the mode when you first set up the hello home action, or it will not offer you the motion sensor trigger possibility. See the following topic:
So easy to use, no custom code required, but not easy to find where to set it up.