Disallowing /wp-content/ for users browsing but not for Google to index files, how to manage?

Has some confusion related to /wp-content/ & other directories in wordpress

Talking about /wp-content/, how to deal with it i. e How to protect from hackers/users browsing & allowing Google to index files like img, pdf effectively?

Blocking via robots. txt wont allow google to index images, files etc & using 403 won't allow anyone user/Google to see it either

I hope I am clear😅

How to deal with this, kindly let me know