I get different results between GA4 and Big Query by calculating Enagement Time.

If i Calculate the SUM of engagement i get following results:

SELECT  
  SUM(b.value.int_value) / 1000 AS total_value,
FROM 
  `praxis-tractor-255014.analytics_251196726.events_20240603`, 
  UNNEST(event_params) AS b,
WHERE 
  b.key = 'engagement_time_msec'
GROUP BY 
  b.key

And in Lookerstudio:

But if i Query for each page the result doesnt match the result in Lookerstudio which is connected direct with GA4:

SELECT  
  b.key,
  c.value.string_value AS page_location,
  SUM(b.value.int_value) / 1000 AS total_value,
FROM 
  `praxis-tractor-255014.analytics_251196726.events_20240603`, 
  UNNEST(event_params) AS b,
  UNNEST(event_params) AS c
WHERE 
  b.key = 'engagement_time_msec'
  AND c.key = 'page_location'
GROUP BY 
  b.key,
  page_location

the same is by Event name:

SELECT  
  b.key,
  c.value.string_value AS page_location,
  SUM(b.value.int_value) / 1000 AS total_value,
  event_name
FROM 
  `praxis-tractor-255014.analytics_251196726.events_20240603`, 
  UNNEST(event_params) AS b
WHERE 
  b.key = 'engagement_time_msec'
GROUP BY 
  event_name,
  b.key

Lookerstudio:

I am not able to find the error by queryy the time by page location or event name.

Thanks in advanced

I was trying like described above the different queries but i was not able to fin a solution by my own or searching on this platform