Query is slow when $lookup

Working with Data
,
2

what index you have on each of collections?
user will have default _id index and the same with rest of the collections but if you have user_id index on address and address_id index on addressComments then lookup will be faster.

also if you are not using project for lookup then you lookup can be simplified ad below:

{$lookup:{
  from: 'address',
  localField: '$_id',
  foreignField: '$user_id',
  as: 'address'
}