What is the yield of ETH stETH?

Could you kindly explain to me what the yield is for ETH and stETH? I've been hearing a lot about these cryptocurrencies and their potential returns, but I'm still a bit hazy on the concept of yield in this context. Could you break it down for me? Is the yield a fixed percentage or does it fluctuate? How is it calculated, and what factors influence its movement? Also, is there a significant difference in yield between ETH and stETH? I'm eager to understand these nuances and make informed decisions about my investments. Thank you for your assistance.