I came across the function list for the Google Data Studio. I've migrated from universal analytics to GA4 and there isn't a "unique event count" metric that I can find.

I've created my own custom dimensions called event category, action, label and custom session id which uses an identical calculation to universal analytics which I'm sending in the events, also sending a event_custom_count dimension with the value of 1

I need to get the SUM of all of my event_custom_count metrics grouped by my event_custom_session_id and cannot find a function or way of doing this?

My vue gtag code:

app.$gtag.event(`fudge_custom_events`, {
  'event_category': `Fudge: ${category}`,
  'event_action': `affiliate:${affiliate}`,
  'event_label': label,
  'event_custom_session_id': sessionId,
  'event_custom_count': 1
})