Tips and hair products I can use for damaged hair?

So I want to get extensions and trim my ends because my hair is really damaged and hopefully it'll be the same texture as the extensions but my hair is curly and I live in a humid climate so I get frizzy hair easily and my hairs stubborn and I sometimes have to fix it in the mornings due to an imprint left on it while I slept or if I tied it too tight. I wish I could do thermal straightening but it's too much money. What heat protectors, conditioners, shampoos, dry shampoos, and oils do you recommend for dry & damaged hair? Also anything that fights against humidity! And I don't know but is it true if you put coconut oil on your hair or olive oil and straighten it, does it fry it? Thanks to whoever answers this ^^