What’s the APR for stake ETH?

I know currently it's possible to do staking using some third parties platforms or validator aggregators. Can anyone say what's the current APR for stake ETH and the expected APR after merge?

Also, will it be a stable and guaranteed APR? Has network usage and charged fees any influence on APR level?

If possible would like also to know how different is the staking APR of you have at least 32E and run a house by yourself. Is it require much technical knowledge to do that?