What I find helpful for CPTSD is a combination of mindfulness, Somatic experiencing, talk therapy and art.
When you get a negative emotion, localize it in your body, imagine it's position, size, colour, texture and find another "safe space" in your body- for me it's usually feet touching the ground or bottom/tights and the feeling of safe chair under me) then shift the attention from one place to another, imagine the pulsation and feeling of contraction/relaxation. For me, this works pretty well. I do exercises like tapping and massaging my whole body while thinking "this is my hand, this is my shoulder...". It helps with establishing boundaries and mainly to bring me back from my mind and overthinking back to reality.

As has been mentioned here, I love paining, too. I'm definitely not an artist and I've never considered myself a creative person. However I find drawing child-like pictures of my trauma and emotions very helpful. It helps me process on a deeper level than talk therapy. Another thing I'm just going to try is intuitive painting.

I also find talk therapy helpful, it helps me solve the puzzle of my life, explain why I am where I am, and sort my feelings and experiences. It is great to have someone you can trust who listens to you.

Another thing I do is mild exercise (fast-paced cardio and anything competetive or goal-oriented is too stressful for me and causes me anxiety). However, when I'm able to do just a little exercise with no particular goal in mind, such as swimming, walking while mindfully observing my surroundings (eg autumn leaves) or slow-paced yoga I can feel the endorphines.