Hi Adib!
I saw this question about the datastores before and it was answered then with this:
Redis is used for caching so it's fairly 'lightly' used, you don't need many resources for it. Mongo is for artifacts, system info and some metadata. Elastic is for events and logs, this one might require more resources depending on your usage.Hope it can already help a bit!

Also, if you have experience running on premise (containerized) - I would love to learn from your experience, particularly about datastore management (if any) when the data grows (it tends to do that sometimes 🙂 ). Thanks!