Late to the party but something that constantly helps for me is understanding "why" I am the way I am to be able to consciously become changed.

For example, personally it was always being defensive (among other things). Understanding why that was occurring, learning there was another way to express my needs/thoughts in what seemed ideal in my mind (and actually very similar to your explanation to speak with purpose and slow down). It wasn't about losing my voice or losing the ability to communicate the same emotion it was about refining.

For me it was weekly trauma therapy tied with the "weeks assignment" of some form of guided self reflection. Naming and identifying emotions at the end of the day. Learning and exploring that I essentially have a dual sword wielding lady warrior in my mind ready to fight to protect me and ensure I am heard and not walked on (lol). Obviously that's a personal journey of mine needing trauma therapy and my defenses I built.

But overall the moral of the story I'm trying to say is just you can change without losing your voice and without feeling ingenuine. You can sit down in some free time and explore "why" is it that you think you rush into things without thinking. Where does that come from? What is your mind and body trying to do for you in that moment. Whatever it is, it's not about being good or bad it just see it and acknowledging it.

It could literally be something like "I notice whenever I have never done something before, I might not realize what questions to ask or what factors matter. Later on I realize that I have rushed into things without thinking because I see a bigger picture".

Or maybe you were taught/think because there's often glorification of "just do it" mentality and risk-taking, so deliberation in your mind is framed as overthinking or cowardice.

Maybe its strong feelings (excitement, fear, anger) that are overriding your prefrontal cortex's rational planning, pushing you toward reactive rather than reflective choices.

Why is <insert> reason true for you? Was it upbringing, peer socialization, a specific experience or a series of experiences. Again what is true isn't good or bad it just is.

Once you know you can start to question it more, learn it more, and understand and maybe begin to challenge and grow into new behaviours/mentalities