After looking at various browser alternatives to Firefox (my daily driver for years), I decided to try LibreWolf and the transition was trivial on a Debian based system (by HN standards). My extensions even ran without logging in (YMMV).

First install LibreWolf: sudo apt update && sudo apt install extrepo -y sudo extrepo enable librewolf sudo apt update && sudo apt install librewolf -y

Second: After closing Firefox, copy Firefox profile (in ~/.mozilla/firefox/) to Librevox profile (in ~/.librewolf/).

Note: I copied the profile into the default profile (as seen in about:profiles) not default-default. I then launched the profile and all my tabs were restored, bookmarks, logins, etc. I will update if something seems broken.