I do think a document DB is a perfect fit for our schemaless data
Also Mongo DB sharding may be cost more effective than Cosmos DB partitionining paradigm where its more costly to shard data across different servers
My understanding such a paradigm is cheaper in mongo
However It takes effort to go through new vendor engagement at my company, adding vendors adds yet another place to manage access/permissions (since it’s not in already established technology like cosmos or google firestore), and you need to first provide hard evidence it will be a better choice
Not sure if anyone has experience migrating from SQL server to document DB and face objections from company staff like why not use Cosmos etc