I would like to inquire about forehead fillers for my flat forehead.

I am writing this inquiry because I would like to get forehead fillers.
I am concerned that my face looks lacking in dimension because my forehead is usually somewhat flat and lacks volume.
Especially when looking at my profile, my forehead line is uneven, making the overall facial balance look lacking, so I would like to naturally add volume.
I decided to consider the procedure because I want a natural line that suits my face well, rather than an overly convex forehead.
Since this is my first time getting fillers, I am wondering what amount is suitable for my face shape and if I can achieve the desired results with just one session.
I would also like to consult on whether it is better to fill only the center of the forehead, or if designing the temples and the area above the eyebrows as well would yield more natural results.
I tend to use my forehead muscles a lot, so I'm also curious how long the results of forehead fillers last!
My skin is on the thinner side, so I am worried that if I have a large area like my forehead treated, it might look very uncomfortable.
I am also curious if you would recommend fillers for such a large area, even on thin skin.