i think the death note probably doesnt go by “legal” name but rather the name you tie your identity and self image with, and it makes no sense for the death note to abide by laws constructed by humans anyway. so i think that if youre trans youre safe from light yagami because hes transphobic and wouldnt write your actual name in it even if it was life or death
this person gets it
if your chosen name is similar to your birth given name (like elliot page) then light would die after a few attempts because one of the rules is that if you intentionally misspell a name multiple times, you fucking die instead of the target