Hiya - I have a different idea...
Have you considered trying Curly Girl?
Reasons for it - low maintenance, costs less, less time, healthier nicer hair..
I too have thick curly hair. Used to straighten it - but it ruined it. Used to hot brush it - ruined it. More frizzy, high maintenance etc.
Saw endless mentions of curly girl, read about it and went for it.
Here is my routine now -
No products, as can't wash them out using no sulphate shampoo. Products and stripping the hair go hand in hand, so if you stop stripping the hair, you can't use products...
Started with two shampoos - co-wash (conditioner for shampoo) and no sulphate shampoo, alternating. I use Faith In Nature range, inexpensive and natural.
This alone stops your dry hair from being stripped.
Then I learned that you have to find out whether your hair strands let water on or not. Mine do not, they are low porosity. That was when I realised that my cheap conditioner, the aloe vera Faith in Nature one, really thin consistency, worked the best of all. Thick oily conditioners sat on top of the cuticles and didn't go in, weighing the hair down.
To find out your hair type, get a strand and put it in water. If it takes on the water, it is high porosity, if it doesn't it is low. Then you can choose which products to use.
So I'm using a non stripping shampoo, the right conditioner. I comb in the shower with conditioner on. I rinse out, then finger brush through, towel for five minutes only, and a little of the conditioner on the ends. Then leave to air dry - seriously. No styling, nothing, just do the parting and leave it.
I look at photos from ten years ago and see that my curls are much better, the hair is softer and shinier. It fits with my aging learning that natural is best.
On a daily basis I use an Afro comb to lift the roots, and spray every morning with a water / conditioner mix to refresh the ends.
And my most recent best addition to this simple routine is - a heated hair cap £19.99 from Amazon. I wash, rinse, put conditioner on, pile loosely and put in cap, then sit under the heated cap for 20 mins - game changer. This opens the cuticles and allows the conditioner to go in more. Hair is even softer now.
All in all, I recommend stopping heat treatment as it ruins hair, stopping using shampoos that strip the natural oils and start using the heated cap.
No what you asked for, but thought I'd say anyway in case it is of use.