Error: Call to undefined method MongoDB\Collection::getMongoCollection() - mongodb

Question

I've upgraded an app from PHP74 to 81 and doctrine/mongodb-odm 1.x to 2.x.
A call to this method
private function getLoginsForPipeline(array $pipeline)
{
$collection = $dm->getDocumentCollection(LoginTrackerModel::class)->getMongoCollection();
return $collection->aggregateCursor($pipeline, ["allowDiskUse" => true]);
}
where $pipeline is defined as:-
$pipeline = [
[0] =>
array(1) {
'$sort' =>
array(1) {
'date' =>
int(-1)
}
}
[1] =>
array(1) {
'$group' =>
array(2) {
'_id' =>
string(5) "$user"
'lastLoginDate' =>
array(1) {
...
}
}
}
[2] =>
array(1) {
'$match' =>
array(1) {
'lastLoginDate' =>
array(1) {
...
}
}
}
];
returns:-
Error: Call to undefined method MongoDB\Collection::getMongoCollection()
So, looks like getMongoCollection() has been deprecated in doctrine/mongodb-odm 2.x
I have a hunch we can replace
$collection = $dm->getDocumentCollection(LoginTrackerModel::class)->getMongoCollection();
with:-
$builder = $dm->createAggregationBuilder(LoginTrackerModel::class); in 2.x
does anyone know how/what we'd replace
$collection->aggregateCursor($pipeline, ["allowDiskUse" => true]);
with in 2.x?
Am I on the right track with something along the lines of:-
$builder
->match()
->field('lastLoginDate')
->group()
->sort('date');
$result = $builder->getAggregation();
I'm not 100% since getAggregation() != aggregateCursor()