So this redeem script is same as public key?
I mean for multi-sig wallet it's harder to find public key if there's output transactions?
Bitcoin scripts are essentially smart contracts. Each time you create a transaction you are providing an "unlocking script" that provides required data and commands that can "unlock" the coins that are available on the blockchain. This script can be a simple signature + public key or a more complex one that contains conditions (branches), timelocks, hash operations alongside public keys and signatures, etc.
If all 3 address's types reveals public key when you send bitcoins then what's the additional advantage of using newer btc address types say Taproot one's (except the lower fees benefit) ?
Lower tx weight hence lower fee.
Help increase block capacity (improve scaling).
Faster verification time for full nodes.
Avoid malleability problems.
Access to new features introduced in newer address types such as public key aggregation in Schnorr signatures.