They say the scalp is skin, so I am curious about the standards for scalp care.

Recently, I have been hearing the saying that the scalp is also skin quite often.
So, I started rethinking scalp care.
I thought that just shampooing well would be enough, but it seemed that wasn't the case.
There were also many people who used scalp scaling products or scalp tonics separately.
I wondered if these products were actually necessary at that stage.
It is even more confusing because there are days when my scalp feels dry and days when it feels oily.
I am also wondering whether it is better to wash my hair frequently or to reduce the frequency.
I would also like to know if the care method needs to vary depending on the condition of the scalp.
I was also curious if the scalp is divided into types, just like facial skin.
I am not sure if adding products without criteria is the right choice.
I am wondering if scalp care requires steps, just like skin care.