probably some combination of
1) basic verification (reservation, confirmation, owning car, etc)- shows having skin in the game. if they dont want to do that, then they can stay a lurker and just use the search function
2) tags- rn, the tags we have aren't that useful. like im a "well-known" member, even though i really shouldn't be. i just read a lot and asked a lot of questions in the beginning. # of messages shouldn't be the main factor in giving these tags. additional tags such as ownership duration, etc should be added. personally, i'd like to add occupation and age (i know that's in the user profile page), but having it shown on the side probably is more useful.
3) small questionnaire/quiz- some fb groups do this before admins approve request to join
4) some sort of wiki FAQ sidebar- directs a lot of common questions and info to the mega-threads that we have.
5) more active moderation- sorry mods

, but if certain basic low effort question/threads keep popping up, lock the thread, direct them to the mega-thread (like how some mods have been doing with the EV tax credit discussions derailing other threads), and give them a warning. we're all grown ups here. using the search function should not be that hard.
as for a lot of the FUD, that's a lot more subjective. personally, i enjoy reading certain people's posts about the shortcomings, because they tackle it in an objective and systematic way. unfortunately, they are in the minority. most are emotionally charged "woe is me" rants.