https://arxiv.org/abs/1710.09437
https://arxiv.org/abs/2003.03052
To learn about the sharding plan and various other stuff in the roadmap, this is a great technical overview:
https://members.delphidigital.io/reports/the-hitchhikers-gui...
Hopefully you’ve heard by now that Ethereum has pivoted to a rollup-centric roadmap. No more execution shards – Ethereum will instead optimize for data-hungry rollups. This is achieved via data sharding (Ethereum’s plan, kind of) or big blocks (Celestia’s plan).
I've been following crypto for years and could probably explain Bitcoin in a pinch, but I'll cheerfully admit I have no clue what that means.
https://eth2.incessant.ink/book/00__introduction/00__forewor...
Bitcoin is a very simple system and very limited in its capabilities, but as far as modern blockchains go it is like the early room-size computers, Ford Model T, or Wright Flyer.