How to set the light state back after blinking

The post talks about a global variable, not Items.
You could keep many such in a Map (array) and key by Item name.

Though you can use a Item if you wish.
Then you might put them in a Group and use “Associated Items” naming conventions to make it easier.

Or you could use one of the persistence services to store and retrieve Item states as and when required, in a rule.

Or you could use store/restore states