Sometimes when the browser starts, it thinks there was a problem and creates a new profile. While the old data is supposed to be copied to the new profile, sometimes it does not happen.

Let's start with this first; https://support.mozilla.org/en-US/kb/how-to-fix-preferences-wont-save

Note: Some software, like Advanced SystemCare with Surfing Protection, can protect files in the Firefox profile folder against changes. If you have such software then check the settings or uninstall this software.

Macs: Make sure you install Firefox properly and that you do not run Firefox from within the DMG (Disk Images) file. https://support.mozilla.org/en-US/kb/how-download-and-install-firefox-mac

Note that the System Details list shows you run an outdated Firefox 85 version.

• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.16; rv:85.0) Gecko/20100101 Firefox/85.0

Could you please update to the current Firefox 92.0 release.

• https://support.mozilla.org/en-US/kb/update-firefox-latest-release
• Help -> About Firefox

If there is a problem with updating or with the permissions then best is to download the full version and trash the currently installed Firefox application to do a clean reinstall.

Download a new copy of the Firefox application and save the Disk Image file to the desktop Firefox 92.0:

• 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.