How big do you think your application code is going to be? There's not much point making your life a lot harder for the sake of about 15 extra KB for example. I

How big do you think your application code is going to be? There's not much point making your life a lot harder for the sake of about 15 extra KB for example. If their internet connection is that bad then the web page probably shouldn't contain a single medium sized image on it. That's a tiny amount of data to be worrying about. You'd be better using something small and efficient like Vue to get it released and optimise it later if it's successful. Optimising now for extremely small file sizes doesn't sound like a good idea to me in terms of getting it finished. The reality with side projects is they're much more likely not to be used because they're not finished, not because they're a few KB too big.