Hi Elsa, unfortunately, Firefox does not keep a backup of browsing history (or download history).

MacOS has a backup feature named Time Machine. There might be a backup of the places.sqlite database file in Time Machine. I don't know the safest way to explore that possibility (I'm a Windows person).

Primary location in a hidden location used for the main profile that keeps your personal data (Root Directory on about:profiles).

• ~/Library/Application Support/Firefox/Profiles/<profile>
• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data