Hello @dzz, welcome to the MongoDB Community forum!
You can write an Aggregation Query to convert the data from the string type to double. First, use the $substrCP operator to get the number part of the string “$10.99” as “10.99”. Then apply the $toDouble operator to convert the string to the floating point value (there is no “toFloat” operator).
To perform this as an update operation (i.e., change the values in the database, use the Updates With Aggregation Pipeline feature). For doing a bulk update use the db.collection.updateMany() method.
You can do this operation using the MongoDB NodeJS Driver APIs (JavaScript code) or the PyMongo Driver (Python code) APIs.