mongo is a document store database, basically its a complex key value pair. mongo was created to store JSON objects over a decade ago during the rise of javascript. despite its popularity and ease of use, its a poor data storage mechanism at scale
Scylla and cassandra like nosql would also be appropriate. I think the best is a combination of multiple different stacks, even transactional maybe on top. I wouldn’t recommend mongo it doesn’t scale. Xoken vega looks promising.