unique ID of a row changes every time that I modify this row (using an action button), it’s ok?
No, its not ok. The UniqueId should not change and can cause issues. Can you provide more details on how you are modifying the row?
Don’t use UNIQUEID() as part of an app formula, which get reevaluated every time a row is updated. Best to use it in an initial value expression, which get evaluated only once when the row is created.