Firefox in Cooker just updated to 104.0.1 and it appears to have reset all of the previously saved profiles. The ~/.mozilla/firefox directory has three profiles, various ID numbers with .default, .default-release and now .default-release-1 on the end. All of them (including the oldest, dated August 11) launch Firefox anew, previously saved Bookmarks, Add-Ons, gone.
about:profiles will allow Firefox to be relaunched by making one of the profiles as the new default, all of them now start Firefox anew.
I just update one Cooker system to firefox-104.0.1-3.x86_64 and my old profile was still intact.
It is not unusual that the developer has to rebuild FF 2 or 3 times for each new version before everything is OK. This takes place in Cooker so ROME and Rock users don’t see this. (Normally.)
Edit-again: Obviously FF does not want people to keep reuing the same profile. I do not much like this. So whenever I see a FF upgrade I always open it from terminal with firefox -p and use the old profile. This probably won’t help you now but may in the future.
I can only report what I see. Here it does create a new profile every time it is upgraded but the old profile is always intact. This has been the case for a very long time.
What ever you lost is might still be somewhere in your ~/.mozilla folder.
Edit:
Workaround: Whenever FF is upgraded I try to be sure to open the new version from terminal with firefox -p and in that case it usually opens to the old profile and no new profile is created. I do not know why it works this way but it does here.