i cannot give you advice here. i can only tell you my understanding of my own psyche, with the disclaimer that i am not very mentally healthy, so i might be doing a few things wrong.

for one, i both hate lying (even subtly) and am very afraid of conflict, so i've developed a lot of social strategies to balance the two, basically saying what's on my mind but in a way that makes an adverse reaction less likely. i will only outright lie when i feel i am in genuine danger, but i do bend the truth sometimes to get around a potential conflict. also, weirdly enough, my feelings in this regard are almost exactly the same online as offline, anonymous or not.

i also seem to have a different response to social adversity than others. one of my greatest fears is that people only interact with me because they have misidentified me as a good person. i deal with that by being as honest and vulnerable with friends as i can, so i know they know who i really am. i get embarrassed occasionally, and the memories torment me for years afterwards. but i use that to hone my strategies for avoiding embarrassment while staying honest. (also to develop new complexes and worsen my self-hate, but that's beside the point.) in situations where others would find a reason to hide themselves and their interests, i rarely find those reasons compelling. and sometimes i find new reasons to open up.

that probably isn't helpful (and remember the disclaimer: this might not be healthy), but i hope you get better about vulnerability. it's not as hard or dangerous as it seems. outside of the internet, most people aren't assholes, and the assholes are easy to spot. hiding is not as necessary as you think.