Count the same activity if it occurs more than 2 times

In a specific case? use INDEX_ACTIVITY_TYPE() - https://docs.celonis.com/en/index_activity_type.html the MAX value will give you the total repetitions of that activity for that case.

If you just want to count how many times the same activity appear, use a OLAP with dimension the activity name, and KPI count_table(activities_table)

HTH