Hey @hauwi!
While it's not a built-in feature, there are a few ways to approach this problem.
The most straightforward way is to create a new field that you can use to represent the state change. A checkbox is an easy pick, but you could use other field types depending on your required level of complexity.
Change the permissions on that checkbox field to restrict anyone from editing the value of the field. You will, however, want to leave the option enabled for automations to edit the field value.
Now, head into the automation workflow in question. Here, you'll need to do two things.
First, add a new condition to your trigger that specifies that the trigger should not continue if that newly created field returns true.
Lastly, in your Update record action, have the automation set the value of the checkbox field to true.
Now, I can foresee a world in which you might want to manually retrigger an automation flow for a record. If that's something that's applicable to your use case, you can update the field permissions to only allow specific users to edit the values of your checkbox field.