Bkt Hair Which Chemical Hair Straightening Method Is Best To Do On Your Hair?

Which Chemical Hair straightening method is best to do on your hair? - bkt hair

Set up and chemicals of the following methods:

Japanese straightening
Brazilian Keratin Treatment (BKT)
Keratin (smoothing) Complex (Coppola)
Relaxing ordinary

I wanted to know the pros and cons of each judge, which would be my best solution. I begin with the most kinky / curly hair 4a/4b, we must work in the hair (know for damage to my hair and I).

I've heard some of the disadvantages of each:
With Japan: not for curly hair (recommended for sensitive)

SCD: contains formaldehyde, can cause mild to severe respiratory eyes, skin irritation

Coppola: contains aldehydes, eye irritation and respiratory problems

Regular rest: you can burn through the skin (I experience it first hand), can lead to hair breakage.

My plan is to get one, but I want the lesser evil of four (JK)