You can try the Garnier Whole Blends but if you're hair is extremely damaged...I'll recommend shampooing less and co-wash at least 2 times a week. They have a lot of inexpensive co-wash treatments which is basically a cleansing conditioner. It helps keep your hair moisturized and doesn't strip the needed natural oils from your hair like shampoo does.
Also trim the damaged ends and seal your ends with a mixture of Shea butter, coconut oil, and avocado oil. You can look online for different recipes.
If your relax your hair, lay off the relaxers for a while and find some protective styles like twistouts or braid outs.
If it's extremely damaged I'll recommend Mazani, Kera care, or designer essential, they all have great reconstructing conditioners and leave in conditioners.its pricey but worth it. I use it my clients that have multiple medications to take and it dries their hair out.
My daughter has long hair that she refuses to let me trim, so the ends get very dry & damaged. She uses Argan OIl and it does an amazing job. And you can find some that is pretty affordable.
Have you tried oils? I have naturally wavy/curly hair, and used to put it through a lot of heat. I started using this oil and can see that i have less frizz, better shine, and it smells great! It is also light weight, and a little goes a long way. I think it would be a great place to start if you are wanting to get your hair back to its healthy state. The loreal oil collection is also an amazing option! My hair feel wonderful after each use. If you buy the shampoo, conditioner, and oil it is a great value.
L'Oreal has a ton of really good shampoos AND misc. items to "fix" damaged hair! After I wrecked my hair, I did get it cut 2 times in 16 weeks; used "L'Oreal products" after that and my hair was just fine!