Which one is gas efficient?

Question

Lets say i want to store some data about each address ,through the mapping. My first idea is: store in struct this way:

struct user {
   address userAddress;
   uint256 someUint:
   string someString;
}

mapping (address => user[]) public addressToStruct;

function storeData (uint256 _someUnit, string _someString) external {
   addressToStruct[msg.sender].push(user{address(msg.sender), _someUnit, someString});
}

But now i have a new idea to doing this but i don't know which one is gas efficient and if one of them is more secure , and idea is that store them as byte:

mapping (address => bytes[]) public addressToBytes;

function storeData(uint256 _someUint, string _someString) external {
   bytes data = abi.encodePacked(_someUint,_someString,address(msg.sender));
   addressToBytes[msg.sender].push(data);
}

Answer 1

just a hint:

Think twice, maybe you can store the data outside of blockchain using events.

(Also I can't find the information to prove my statement,but as i know doing abi.encodePacked costs like 800 gas)