Have wars become worse after WWII?
That's an opinion question. What does "worse" mean to you?
Read, read, read, and take good notes. Then let us know what you decide.
https://www.google.com/search?q=wars+since+ww2&rlz=1C5CHFA_enUS705US707&oq=wars+since+&aqs=chrome.0.0j69i57j0l4.5147j0j9&sourceid=chrome&ie=UTF-8