Not a fan of the new look. If you’re in the same boat, plug:
about:config
into your URL bar, and search for:
browser.nova.enabled
Toggle it to false using the button to the right.
There are functional changes that Nova also introduced: this won’t effect those - only the aesthetic.
You can use Firefox ESR, the extended support release which receives security updates but doesn’t receive feature updates or other major changes.
https://endoflife.date/firefox
Damn, I can’t believe 115 is still being maintained for 6 more months.
Librewolf is based on the main release of firefox, and will probably inherit all the UI changes as Mozilla releases them.