Would it be possible to talk to that person and say sorry, if you feel up to it? They might appreciate it.
Is there a more constructive way that you could use to cope - like a hobby? I do not want to call you toxic or abusive myself, because I was not there and it would not be fair, so I will use quote marks. You say that you are aware of your "toxic" behaviour, but this means that you must have at least some good character within you; since a person who is irredeemably bad would either not care or just not be honest about it. Plus you also said that you have self-banned from the chat to avoid, what you perceive, as hurting others even more - this could suggest that you have empathy.
No. I do not believe that you are a "monster" given the previous part of this post. If you dislike your mothers behaviour then you do not have to be like her. Yes genetic code certainly does influence the development of a human being, but it is not all completely pre-programmed. In fact it is theorised that much of our behaviour is learned and also malleable, so there is the possibility of trying to forge your own personality.