You need to have two different meta queries for the date. One like you have to get the current or active events, this query will not have a “clause”. The second query will be the “EXISTS” query I posted earlier.
Also, you need to check the format of the data that ACF stores. If this is a “Date” field, ACF may not be storing in a standard “Date” format and type' => 'DATETIME' is probably the wrong type to use.
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