I've dyed my hair for a good 10 years or so. ALways tried to stick to my natural colour, but the dye always seems to get much lighter with time. I have decided to go back to nature

I'm in a horrible in between phase actually where I have about 2" of normal hair (roots) which are salt and pepper mixture of grey and darkish brown, then about 6 inches of dyed hair, which although brown at time of dying has lightened and lightened to the point of being practically blond.
Anyway, thinking long term when it is all grey, as well as now to hide the abismal mix of brown grey and blond, what can I do. All hair bands seem to feel tight and give me a headache, must have a big head.
Want to still look youngish! But also smart ish.
I don't really understand where you get these headscarf things that some people wear like giant their bands and they seem to look stylish, but maybe you need big hair?
My hair is very thin and fine and at the nape of my neck at the back and about an inch below the ears at the front.
Any suggestions? I wish I could just wear a hat all day every day.
Plus is there a non chemical way to help with the colour on my path back to nature?