Try to reinstall Firefox in case something went wrong updating.

Download a new copy of the Firefox application and save the Disk Image file to the desktop Firefox 116.0.3:

• https://www.mozilla.org/en-US/firefox/all/#product-desktop-release

• trash the currently installed Firefox application (open the Applications folder in the Finder and drag the Firefox application to the Trash) to do a clean reinstall
• install the new version that you have downloaded
• https://support.mozilla.org/en-US/kb/install-firefox-mac

Your personal data like bookmarks is stored in the Firefox profile folder, so you won't lose personal data when you reinstall or update Firefox, but make sure NOT to remove personal data when you uninstall Firefox as that will remove all Firefox profile folders and you lose your personal data.

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

I'd recommend resetting the browser. You can do it manually by deleting the preferences files from the Library folder on Mac. Also, there are many third-party tools that provide such an option, for example, App Cleaner & Uninstaller.