So I've come out to my parents twice. I told them I was he/him and my name was Tord in a letter. My sister gets it extremely easily after a few conversations. My dad didn't let my mom read the letter, said he didn't want to call me "by any name other than [deadname]" so I told them in another letter and the same thing happened. I think I'll just tell my mom in person at this point. Any other advice?
Given that you are 14 and presumably dependent on them could you possibly be in danger (whether just ridicule, pressure or all the way to being thrown out) if you kept pressing on this subject? Your dad seems blatantly unsupportive, you should probably drop the subject with him, especially if it could lead to danger. If you believe that your mother would be much more supportive then maybe you could approach her when your dad is not around. If she is likely to have the same reaction then I would suggest that you shelve the subject until you are in a stable place in your life where them reacting badly cannot hurt you. Keep it between you and your sister, lean on and revel in her acceptance for now.
My mom is extremely supportive, she'd definitely not react like my dad is. My dad already took away my phone and friend privileges due to me not getting one assignment done, I'll definitely avoid speaking with him about it.
Not accepting who you are and restricting you for not doing schoolwork are two entirely different things. The first is reprehensible while the second is his responsibility as a parent.
