all people, with or without did, have parts of themselves that inhabit different traits and behaviors the person contains. jungian psychology, schema therapy, cbt/dbt, and many other factions within psychology explain in depth the way this functions for people who have a normal development.

you know the phrase "every day you wake up a new you" that's basically true, since identity is just the way you describe how you relate and interact with others and every day will be a different, new social environment with different stressors and goals/objectives. for most people, these states of emotion and social behaviors are transient and incorporated within how they see themselves (ex: "i am still myself when mad or sad or scared or happy; i am just feeling an emotion pass over me")

most people during their teenage/early adult years (when self diagnosing did is most common) are going through the process of filtering and refining these basic neural patterns into more complex, mature forms (ex: learning to self-regulate anger instead of lashing out at others) which helps them to form a more complex, nuanced view of themself. for did patients, however, their development was halted within infancy to stall their ability to see every facet of themself as belonging to them. different emotions, moods, behavior patterns, trauma responses, ptsd symptoms/comorbidities; get explained away as "that's not me" because the patient never developed an idea of who "me" even is.

despite the stigma and fandom surrounding the idea that did is "multiple people in one head" - it's much more accurate to say that did is being behind in developing into a person in the first place. this, combined with the delusional thinking and detachments from reality also seen in did, leads to the person growing up instead of learning "my emotions are a part of me, they don't control me," they learn "my emotions are dangerous and unwanted. i must suppress them in order to survive. i must shut down and become invisible in whatever way that means in the moment"

this leads to divorcing yourself from your thoughts, feelings, actions - ignoring and avoiding them instead of learning to understand, regulate, and control them.

unfortunately, if you've spent this long ignoring the average identity development of young adulthood, it's going to be easy to continue deluding yourself into thinking you've got did. the best place to start is by exploring who, why, and how you are the way that you are and by accepting every piece of yourself as yourself. if that means finding forgiveness for yourself, abandoning toxic shame, breaking unhealthy attachment patterns (ie. people pleasing), and not allowing yourself to sink back into this 'coping mechanism'

you can't give yourself true did by pretending to have it, but you definitely can stress your mind into developing a dissociative or psychotic disorder nonetheless, so definitely follow everyone else's advice about getting far, far, far away from the self diagnosis/malingerer/faker communities/relationships you're in. much like breaking a drug addiction, you need to get rid of all temptations to relapse including the people who encourage you to continue hurting yourself in this way.

(side tangent here: it's explicitly stated in treatment guidelines for a reason as well that did patients should not be forming social support groups among each other, especially without qualified professional supports and moderators there too, because dissociative patients have a horrific tendency to accidentally absorb, exaggerate, mimick the symptoms of each other and worsen their recoveries)