How to search for an object without knowing its position in the DB

So I am trying to search for an object/field - let’s say it’s called "my_field"

now, I want to check the database to see if it exists. However, it may either be at a primary level
example: db.mycollection.find({ my_field : {$exists : true} })

Or, it could be in an array like db.mycollection.find({ “1.2.3.my_field” : {$exists : true} })

Is there a way to search for "my_field" without knowing the location of it?
What would the solution be?