Try extracting the timer out to a float that is a blackboard key. Then you can access it’s value / change it in different blueprint tasks & services.
Melee attack count
Ranged attack count
BB keys
Attack methods
Check distance service
You can then use blackboard condition nodes to check the elapsed time
Target Find done before move resets the timer once a target is found => then next node is moveTo target actor
I’m sure you can build the final tree with bb conditions and timer key & distance checks.