The two approaches are very similar, but I’d go with the first approach because in your case you are searching for a specific email address to compare it to only 1 thing (email) Do search for >> email = Request Data's email.
Returning 1 thing:
{
"email": "email@example.com"
}
vs. if you do each item's email.
[
{
"email": "email@example.com"
}
]