Do not remove them in loop. Remove all of them together.
//..
wixData.query("Prospects")
.eq("name", $w("#dropdownName").value)
.limit(1000)
.distinct("_id")
.then(results => {
return wixData.bulkRemove("Prospects", results.items);
})
.then(res =>
//put the code you want
})
.catch(err => {
//code for err
})