Waterfox looks worth a try, but I opted for LibreWolf because it's verified on Flathub and Waterfox is not. It looks like the Flathub version of Waterfox was packaged the same BrowserWorks Ltd that makes Waterfox, but they didn't take the extra steps to get verified so we can't be sure. Hopefully they can remedy that. Browsers are too important to install from untrusted sources.
For what it's worth, it's the opposite situation on Windows: The Waterfox installer is signed (even with an Extended Validation certificate), the LibreWolf installer isn't.
Another thing that surprised me is that there is a Waterfox Android build in the Play Store. Reviews of that are however mixed.
Similar on macOS, the LibreWolf team (somewhat understandably) refuses to pay for Apple's developer account to notarize their builds, so every update I have to remove the quarantine extended attribute (Homebrew can do this as part of updating now) or the OS helpfully tells me my browser is damaged and needs to be deleted.
