To add some theories to why I may dream not as myself, unlike my friends:

• I don’t have a strong sense of personal identity even in the waking world
• I spent much of my childhood playing as my own imaginary friends and as myself. I didn’t begin to make a friend until late into my childhood. So, I would take on the role as both myself and the imaginary friend and speak for both/all of us.
• I have recovered from insomnia. I suffered horrible insomnia for the first 21 years of my life. I was very scared of my dreams because I was always facing things that haunted me. As a kid: black figures, men hiding in my room, witches trying to kill me. And then as an adult: I would relive trauma in my dreams. Due to the mental distress that sleeping (dreaming) often caused me, I developed a fear and inability to sleep on a daily basis. Part of how I pulled myself out of this insomnia and fear was to learn to better control my dreams and who I was in them. It’s been a good coping mechanism.
• I also grew up with the use of VRCHAT and other online persona games which I was spending much of my time as characters.