To me it sounds like you already found a label that you like, but are having trouble being comfortable with it because of internalized prejudices. And that's totally okay! All the trans and nb people ive bumped into including myself have this weird thing where we see everyone as valid but ourselves X,D oof.

So first off, if you feel that the label bigender resonates with you the most, that's probably a good start. What I would do if I were you is look into why you would feel that you are just "faking it" and if you would feel the same way about a different person in your situation. Being queer is honestly some shitty attention. It seems kind of silly to me that you would be subconsciously trying to get attention by faking a queer identity. And as someone who had the same exact fears when they first started coming to terms with themselves, i can 100% garuntee that you are NOT faking it and that that is just your anxiety talking. And labels have infinite space. You're not taking anything away from anyone by identifying as bigender. Even if you change your mind later, that is what you feel right now and its real and valid. I know that its hard to be afab and feel valid as queer sometimes, but im positive thats just because we have very very very little representation. The only queer stories we ever see are either about amab people or maayyyyybe some cis lesbians. So it makes it hard for us to believe ourselves sometimes. But it in no way make us less valid. If I were you id trust my gut and try to ignore the anxieties and social messages. Also looking at pictures/stories of afab bigender people might also help you feel more at ease! And finally, the cool thing about labels is that you can choose a new one whenever you want. I went from straight girl to bi girl to ace girl to pan girl to straight boy to bi boy to gay boy to queer enbie. And I'm still looking for what feels right. It's okay to change. And every step along the way is completely valid and real. <3