You need to see a psychiatrist to diagnose you with something. He'll suggest you go through therapy and all that for some time, and you should do this. In the US when you apply for SSDI, you will likely get rejected the first time. You have to play along with bullshit for a while, just how it is. Getting on SSDI without a facility to back you up and a lawyer working with you is very difficult, if not even possible.
Attempting to fake mental illness is highly unlikely to work, so don't try that. If you're posting on incel boards, there likely is something wrong with you, so just roll with it.
Once you're in, the only thing you need to do is say everything that social workers want to hear and nothing else. They are your enemies, never trust them.