The reason it takes so long for validators to exit the chain is because that’s part of the project’s design. Staking is an important part of maintaining the security of the Ethereum blockchain, and if too many validators left the chain at once the security of ensuring that transactions and blocks are added to the network could not be guaranteed. So the number of validators who can exit at any given time is subject to a hard limit. When withdrawal requests pile up, the exit queue backs up.
Source: https://www.coindesk.com/tech/2023/05/03/coindesk-validator-zelda-successfully-exits-ethereum-as-withdrawal-queue-shrinks-to-9-days/?utm_medium=referral&utm_source=rss&utm_campaign=headlines