Librewolf sounds perfect for you on Linux. On the ethical side they use the ‘no AI’ version of duckduckgo as the search engine and disable DRM by default. These are nice touches that I appreciate.

I can’t think of any tradeoffs.

Agreed. It’s my single favourite piece of software.

I’m annoyed by the new Firefox UI.

Try Librewolf, you can turn it off in the settings.