So research heat and chemical free methods like wet wrapping. There is no way or chemical treating or heat styling your hair straight without significant damage, it just does not exist. Any method of 'stretching out' curls will weaken the protein structure, because there is a direct relationship between the strength of your hair and curl pattern. Basically hair is strongest in it's natural formation, anything else weakens the chemical bonds.
Ultimately it's your call, you may feel you are willing to accept damaged but straight hair, and that is fine. Many people take years or decades to get to the start of their natural journey and some never change.
Or research different cuts and lengths, half ups and full up dos, high and low volume, side or centre part, bangs or face framing layers, longer at the back than the front. Once healthy your curls will have much more bounce and shape, they can't possibly not suit you in every single hairstyle - there are SO many options.
Lots of helpful articles here
THE NATURAL HAVEN: Straightening Hair - Relax or Heat?
THE NATURAL HAVEN: Mid shaft splits: cause and prevention
THE NATURAL HAVEN: Heat Training: Her Hair is not Your Hair
THE NATURAL HAVEN: Why is my hair breaking? Erm.......because you broke it!
THE NATURAL HAVEN: Tiny Wisps of Hair: Is Kinky Hair Weak?
2a-2c, medium texture, porous/ colour treated. Three years CG, growing out mechanical and chemical damage = breakage and very high porosity. Past armpit length heading for waist.
CO-wash: Inecto coconut
Treatments: Komaza Matani, coconut oil, Hairveda Sitrinillah
Leave in: Fructis Sleek & Shine (old), Gliss ultimate volume, Inecto argan
Styler: Umberto Giannini jelly, Boots Essentials gel
Experimenting with: going back to basics