UCAS application

Hello, I took a gap year or two, and now I'm looking to go to university. I'm currently working on my personal statement but I have realised its hard for me to complete at a good standard because I haven't fully decided the subject I want to study. originally my idea was to apply at different universities and different courses and then choose the one I prefer depending on what I got accepted on to. However I'm afraid if I don't make my statement personalised to a specific subject then it won't be good enough. My grades are not the best and I wanted to give myself the best chance possible of getting into uni, studying either sports and exercise or archaeology. I was hoping to keep my options open.Does anyone have advice on if I should choose a subject, or if you have any advice on how to write a statement when applying for different courses? Many thanks Jess