Since you started discussing everything about decentralized systems and also blockchain. I would like to talk about blockchain and Ethereum nodes.
Depending on the type, nodes store only part or all of the blockchain data and are divided into:
1) Full nodes. They maintain the entire network, load and validate each block with transactions based solely on the consensus algorithm, and are completely independent. Full nodes reject blocks or individual transactions that contradict the consensus. Such a node has a complete copy of the blockchain network data.
2) Lightweight Nodes. They represent a computer with special software connected to the blockchain network. Lightweight nodes do not store all blockchain data, but only block headers to authenticate the transactions they contain.
If you are so interested in the topic of nodes and blockchain, read about the eth_getblockbynumber parameter in blockchain and nodes. More knowledge - more possibilities.