

The problem with forks is that you need to trust the original party (Mozilla) AND the developer of the fork. Also, that fork will inevitably lag in security updates coming from the original party.
Firefox is still pretty customizable with user and enterprise policies, and most telemetry can be disabled. They have shown that they listen to their userbase, even if capitalism forces the for-profit part to make cuestionable decisions.

Yeah, both Phoenix and Dove (Thunderbird’s counterpart) are two projects that I do recommend, as they are the best example of what I mention.