Validators secure the relay chain by staking DOT, validating proofs from collators, and participating in consensus with other validators.
These participants play a crucial role in adding new blocks to the relay chain and, by extension, to all parachains. This allows parties to complete cross-chain transactions via the relay chain. Parachain validators participate in some form of off-chain consensus and submit candidate receipts to the transaction pool for a block producer to add them to the block on the relay chain. The relay chain validators guarantee that each parachain follows its unique rules and can pass messages between shards in a trust-free environment.
When you stake via the Lido protocol, your stake is automatically distributed across validators chosen by the Lido DAO, so you don't need to choose validators to stake yourself. The Lido DAO keeps the actual validators list efficient and decentralized to maximize your staking rewards.
The Lido DAO will choose validators on the basis of their own stake, amount of validator nominators, average era points, identity, and commission.
Choosing a validator list that would maximize staking rewards is a non-trivial task that requires the Lido DAO’s permanent participation