Check out Mullvad Browser. It’s created in partnership with the Tor Browser, but optimized to be used for the Clearnet. You don’t need to use Mullvad’s VPN with it either.
I’m stuck on Joplin personally, but have you taken a look at Standard Notes? I think it checks all your boxes.
You really should have read the wiki before asking that question. /s
My small concern with Librewolf is getting security updates quickly. Cool project though. As I understand, the team has been better about quickly patching security vulnerabilities in recently months too.