Following SERVER-50756, there appears to be a problem with db.stats():
There are two ways to call the referenced stats:
db.runCommand({dbStats: 1, freeStorage: 1});
db.stats({freeStorage: 1})
In mongosh run: test> db.stats({freeStorage: 1}); MongoServerError: scale has to be a number > 0 Expected: Output similar to the runCommand call: test> db.runCommand({dbStats: 1, freeStorage: 1}); { db: 'test', collections: 1, views: 0, objects: 1, avgObjSize: 36, dataSize: 36, storageSize: 20480, freeStorageSize: 0, indexes: 1, indexSize: 20480, indexFreeStorageSize: 0, totalSize: 40960, totalFreeStorageSize: 0, scaleFactor: 1, fsUsedSize: 46888751104, fsTotalSize: 62725623808, ok: 1, '$clusterTime': { clusterTime: Timestamp( { t: 1642786653, i: 1 } ), signature: { hash: Binary(Buffer.from("0000000000000000000000000000000000000000", "hex"), 0), keyId: Long("0") } }, operationTime: Timestamp({ t: 1642786653, i: 1 }) }