Hey Anni
Sadly sometimes there are hair types that just don’t want to work as well as we’d like them to and yours sounds kinda like one of those types. Provided that your hair isn’t in too bad a condition and that you take care of it well, I would give a volumiser or a perm a chance. It’s not as popular now as it was in the 80s but at least you’ll be able to hold a wave or a slight curl if the treatment works. Speak to your local stylist about your options for before and after care as well as the different perming products that they use.