Mixing metrics with dimensions (counif)

Hi everyone!
I’m stucked with a problem.

I have connection to GA4 data with default dimensions and metrics.

I need to make a table of 3 metrics:

  1. active_users
  2. users_form_submit (active users with event_name=“form_submit”)
  3. conversion (users_form_submit /active_users )

The formula for users_form_submit would look something like this,:
SUM(CASE WHEN Event name=‘form_submit’ THEN Active users END)

  • but I get an error

Unfortunately, haven’t found solutions for such case in web, except for scorecards. But what if I want to make breakdown by source/campain/etc?
Hoping for your help.