For me Its quite simple. My brain decided it. Literally. The days I found out I’m trans, my brain would do this weird thing, where I could think about completely different stuff and suddenly my now chosen name would “fly” into my mental Field of View, like an asteroid in star wars or so. I told that name a close friend and 4 weeks later when we went to the club together I told him, that I will stick with it, because I didnt had a better idea (and it was the only name I really felt comfortable with).
I know this struggle! I feel odd naming myself, but those close to me also refuse to offer a suggestion. They all say “that’s too personal a thing for me to choose in your place” or “I’m already bad at naming things so, no”. I suppose that I will have to hear it for the rest of my life, so I might as well like it!
I saw someone else here mention that they came up with a short list of names, then got friends to rate them or vote on them and narrow it down from there. Might be an idea. Thinking about it, you can’t really blame people for not wanting to make that decision for someone else. Although it would make it easier lol.