The Ownable contract better to user one come with openzeppelin but if you want to used to make few change as ,I made is git repo which share above
I have made two change in contract.
Ownable:22 Gas usage when you call msg.sender it will gas to not much but small amount of extra gas, which didn't look to much in one transaction but it will waste of money, So before change new owner, store old owner and user it for event it will save small amount of gas.
Ownable:9 , Modifier didn't to access modifier like public and private because those used within the contract
Foundry is used to test it working and gas consumption.
It is better to used Contract from openzeppelin which is already tested and verified.
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