Assigning a value from my attribute table to calculate field expression

[Madam]

Hello i am currently running into an issue where i am trying to get a value from a table created from summary statistics into my calculate field expression.

Based on what is in the table i wish to take the MAX_DATECREATED value and assign it to Last_Update_Date field in my python script.

How would i go about achieving pulling thr value located in the table and assigning it specifcally to my calculate field expression?

[Madam]

To give addtional context, the model section of calculate field i am trying to convert into this,

Based on the model, how would i take the value found in my Attribute table from summary statistics and assign to last_update_date the exact value found?