Hi! I'm not trans but my girlfriend is a cult survivor. Her experience has some similarities to yours.

Growing up she was taught a lot of purity culture BS that caused her to isolate, suppress her feelings, and generally become a machine in order to protect herself. The journey to becoming a person again, involves identifying negative habits, accepting that you are not broken or immoral for developing them in order to survive, and redirecting yourself to better narratives and habits. A therapist, if you can access one, can help with this process.

I am not a trans. I am a white cis male. I'm including this info because you asked from post transition people, but I wanted to answer anyway.

What you are asking, i.e. "how to get rid of bad habits" is a question most people struggle with when they want to improve themselves, so don't worry if there is no clear cut answer.

I would simply advice you to try to embrace who you want to be and don't be too strict on yourself. Try to be who you want to be and if you sometimes lapse, that's okay too.

If you aren't already, therapy, always therapy, can never get enough of that. Also helped me to find people I could look up to or who shared similar experiences and had the patience to teach me how they got through it. It can also take years so don't feel bad if things aren't clicking right away or if you regress in things especially during times of high stress. Just acknowledge what happened and keep doing what you can. This is part of the biggest factor for me which was just consistent self reflection, which you're already doing by asking these questions. Don't try to fix it all at once take achievable steps where you can.

It took me a while, and that mean boy did not disappear, but I've made improvements towards being a better person. What I did was mind my manners and habits continuously throughout the years, I believe there is no other way.

I don‘t have a good answer here but I wish you the very best!

I don't know if there's any single way to change those parts of yourself. For me, it involved a lot of therapy and learning to interrupt my thought patterns. Cognitive behavioral therapy helped me change my thoughts, feelings, and actions. I originally did a whole write-up on 1 particular analogy that I found really helpful back then, but it's hard to say if one strategy that worked for me will be effective for you. Changing one's self and growing into the person you want to be is hard.

You will always need coping mechanisms. Even when life is going well you can still have bad days. What I did was to find healthy coping mechanisms to use to replace the bad ones. There are many ways to cope and not all the ways work for everyone, so just try them out and see what works. One that I started using very early on was relaxation breathing and another that I started more recently is exercising.

Since therapy has been mentioned a few times already, I would go with something else for a change of pace.

Even the worst behaviour has at least some "positive" or desirable aspects that are important to a person.

So if you find why you tend towards certain behaviour, take some time and effort to isolate these aspects.

More importantly, you then need to find something to replace it with something that contains the aspects you value, but do not have the same harmfull side-effects.

Example: Smoking when you are bored or to keep your moth busy. Instead of "just quitting" (which might be difficult), a switch to chewing gum might be more effective, while stopping the damage smoking causes.

Hope this helps!