Interface scale VS canvas viewport scale

Please separate canvas from interface scale (View>Interface scale). 
I am workin on iPad app, and with 100% canvas scale i have almost 1 to 1 with physical iPad screen size - thats what I need. But also i want to make all UI elements of Figma smaller. I found this settings in View menu, but unfortunately it scales not only UI but everything including canvas - so with 100% canvas scale frame become smaller then real physical size.