The official Ethereum Wiki is one of the best places to learn everything about Ethereum as well as related technologies and protocols such as IPFS, Whisper, Swarm, etc.
Browsing through the wiki you'll find plenty of resources on topics like governance, scaling, sharding, Eth1 vs. Eth2, the official roadmap as well as general research related to Blockchains and Smart Contracts.
Protip: The wiki is community-driven which means that you can contribute by joining the discussions and proposing changes.
- Ethereum Foundation