The Surge: Back End data and Sharding

This post will prove my ignorance, sorry in advance, I am asking after decades working in a corporate infrastructure. Closed. Centralized. BAF. But I need some ammo because I am on an island in my age group getting blasted left and right on anything ETH/Crypto.

Vitalik constantly talks sharding in "The Surge", can someone explain technically what the back end database is? Open Source? SQL/Oracle/Exasol/Azure/Snowflake/Mongo, does it matter or is my brain too old. Costs to scale etc.

I do think massive education of the general public is the number one cock block to changing skeptics minds on crypto, especially the old timers with a lot of money. With a 98% fail rate on the basics. (this looks like a terrible click-bait website but it is actually really good to take this test and show others. https://cryptoliteracy.org/ )

Every Adverti$er knows: "The hardest thing to change is a person's opinion."

Update: In his latest Endgame Address, Vitalik does point us to this paper:

https://vitalik.ca/general/2021/05/23/scaling.html

Real world scale could top out somewhere around 96 Terabytes a year (held indefinitely) but an issue:

"But once a blockchain's capacity gets too high, it becomes harder to store all that data, until at some point there's a large risk that some part of history will just end up being stored by... nobody."