I only use shampoo... do many people use hair essence or protein products?

Since it's summer these days, even my hair roots are sweating, so

My hair feels dry and brittle even after washing it, and it feels like it's falling out every time I touch it. It feels like everything is getting worse because of the heat. I didn't pay attention to hair essence because it was a hassle.

Even something like this isn't good if you overdo it, right?

For now, it’s probably better than doing nothing... but there are so many varieties.