i have a 13 in late 2011 macbook pro. i need safari version 14. what os system can i upgrade to?

A mid 2010 through late 2011 MacBook Pro can be upgraded to High Sierra 10.13.6 but no later version. See: https://support.apple.com/en-us/HT211683

Since you cannot upgrade beyond High Sierra you may want to consider using another internet browser such as Chrome. You can install the latest version of It; it will run on OS X 10.11 and later. See: https://www.google.com/chrome/

Might try this, it's Chrome Browser without google & without Ads...

https://brave.com/