How to journal to productively to help with trauma?

I've been an avid journaler for over a decade but noticed that on some days I tend to ruminate or write about my pain, whether it be from a current situation or from the past, sometimes stretching for a few days. I'm honestly not sure how helpful this is for me.

For those who journal and feel that it greatly helped with their CPTSD or mental health in general, do you have a scope of things to write? Time restrictions? Length? Specific prompts? Or safeguards that won't allow you to spiral? Do you look for patterns later on?

Do you journal about your day (who/what/when/how, important conversations) or do you focus more on thoughts for the day?

I'm open to all sorts of ideas.