Hello, my hair is quite coarse and dry, it is naturally frizzy

I hate it so I blow dry and straighten it to make it look decent!
I know heating products damage hairs (I do use a heat protecting spray). I cannot not straighten it.
I want to know is there anythin I can do to make it look shiny and healthy instead of dry?
I wanted to use oil or something but dont know what type to use? I dont want my hair to start falling out or anything

Any tips or advice wanted as Im getting married in a couple of month and want to look my best