Eversol Stake Pool uses the standard Solana Network Stake Pool Program – "a program for pooling together SOL to be staked by an off-chain agent running a Delegation Bot which redistributes the stakes across the network and tries to maximize censorship resistance and rewards". This program has been audited by multiple security firms to ensure the total safety of funds.
Solana Stake Pool Security Assessment Final.pdf
It is super important for the stake pool program to be open-source and audited. Read about theSafety of Funds in Solana Stake Pool Program.