Hey guys.
What would would be the simplest logic to return apy to a user in a staking smart contract?

Lets suppose there is a erc20 token smart contract which has staking function.
If you buy some erc20 token and stake into the contract then you will get some percentage of APY interest after a week/month.

I am thinking of this solution.

1)developing ERC20 token using openzepplin and add a new staking function in it
2) when a msg sender calls the staking function then the tokens will be stored in a user mapping into the contract.
3) if the token owner is withdrawing the tokens after a month then he will get let say 5% APY for staking.

So the contract will calculate 5% of the staked amount and it will mint the calculated token and will add it into the user mapping.

Is this correct approach? Or please help me refine this idea