I face similar problem with anything above org.mongodb.spark:mongo-spark-connector_2.12:3.0.1
So version 10+ of org.mongodb.spark:mongo-spark-connector_2.12 from https://mvnrepository.com/artifact/org.mongodb.spark/mongo-spark-connector_2.12 are not working with Databricks 12.2 LTS 😣

org.apache.spark.SparkClassNotFoundException: [DATA_SOURCE_NOT_FOUND] Failed to find data source: mongo. Please find packages at `https://spark.apache.org/third-party-projects.html`.

Is there anything that should be done additionally to installing it into Library? Maybe some additional cluster option?