For flows that have already run, it is valid for 30 days, and for flows that are not triggered, it will run as expected as long as the connection in the flow is still valid.
My suggestion is to divide the total number of days of delay into several parts, for example, you can modify a value in the table with a delay of 10 days in the first flow, the second cloud flow is triggered after 10 days because the value is modified, and then enter the delay action again, and so on until the last cloud flow is triggered after 40 days.
