Show the issue. What OS? X11 or Wayland? Could be your theme, I don't have that issue. see screenshot Log into another account and see if you have the same issue. Also try downloading Firefox from Mozilla. Download, unzip, and run firefox-bin from the folder and see if you have the same issue. https://www.mozilla.org/en-US/firefox/all/#product-desktop-release

I missed the 113 releases. When I updated to 114.0.1, I had no minimise, maximise or close buttons unless I had the title bar showing. The menu bar is my topmost toolbar and I could previously get the buttons there by changing the relevant preference from 2 to 1. That no longer works on Linux according to searchfox. org.