Identifying cause of task update Event

[zachomar]

Hello Camunda community,
We using Camunda 7.20 embedded in Java Spring Boot. We implemented an Event Bridge to globally catch various events done during BPMN process.

@TransactionalEventListener(condition = "#taskDelegate.eventName=='" + TaskListener.EVENTNAME_UPDATE + "'", phase = TransactionPhase.BEFORE_COMMIT)
    public void taskUpdate(DelegateTask taskDelegate) {
       ...
    }

We need to implement functionality, that relies on modification of specific variable.
However this event is triggered by many actions and we cannot find an easy way to identify the original action that raised the update event:

Action	Triggers update event	Desired for my cause
Add Comment	Yes	No
Candidate User modified	Yes	No
Variable newly assigned	Yes	Yes
Variable reassigned	Yes	Yes
Variable removed	No	Yes

With respect to this table, is there a way to:

1. Identify Action that raised event?
2. For Variable related Actions, any way to identify what variable was affected? Old and New value?
3. Catch variable removal?