Please tell me how to tame frizzy curly hair.

I have wavy hair, and it tends to be thin and weak.

When I was younger, my hair was so frizzy that I used to get a straightening perm, but now that my hair has thinned out, it's difficult to do that.

It sags if I leave it alone, so I got a wave perm to add volume.

This curly hair just won't go away.

If you just leave it, it gets messy and floats up.

I apply the curling essence I have at home when there is still a little moisture left.

I don't think this is enough.

Maybe I don't know how to apply it properly

I wonder if there are other good products.

Experts, please help me out.