How can I convert a text having a timestamp format to a timestamp?

Hello there, 

Please is there any function on explore that could allow me to convert a text in this format "2022-11-21T15:19:18" to a timestamp.. Indeed I need this in order to catch the first reply time on a ticket when an outbound call happened (generating automatically a private note that the normal first reply time metric can't catch).. Our technology team could implement a trigger that catches that exat timestamp when the outbound call took place but that trigger could be only stored in a text field.. so now the issue is on how to convert that text to a timestamp and then calculating the difference between it and the ticket created timestamp ..

Thanks!!