What is the average expected returns when investing in s&p500 etf vs stock picking?

S&P 500 average annual return is about 8%:

Investopedia on S&P 500 Average Annual return

Average returns for stock picking is harder to quantify. It depends very much on your stock picking skills.

You can expect around 10% annualised returns for S&P 500 ETF based on a 10-years span but past performance does not mean returns are guranteed.

Stock picking can yield you outstanding returns if you know what you are doing. But for most people, ETF would make more sense unless you can deep dive and build your own convictions on each indiviudal stocks.