Can a Person Receive the Same Email More than Once?
In Flows, by default, people can receive an email only once. This is to prevent over-emailing people if a Flow is not configured correctly.
If you'd like them to receive the same email more than once, you can enable that option in the Send Email step. Just switch on the "People can receive email more than once" option.
With Broadcasts, you can send the same email repeatedly.