Use something like this https://www.amazon.com/ORS-Built-Protection-Application-Relaxer/dp/B00E5PWBQC/ref=mp_s_a_1_3?keywords=hair+relaxer&qid=1647468817&sr=8-3
Leave it in your hair for only a partial amount of time, and then wash out. I have very similar hair type as yours and it will loosen the curls without making it bone straight. Just make sure you pay close attention to being gentle around your scalp and the base of your hair. Depending on how fast your hair grows , it will require touch up every other month or so (only at the roots).