Doesn’t have to be world changing or even practical. A project like that would still teach you a ton about storage hardware, how file systems work, programming, mathematics etc. Some of these lessons could even be useful, but above all, a project like this should be fun and interesting.

Why do you think people install Linux and run Doom on all the weirdest hardware they can find. This is the spirit that drives innovation.

Don’t let expectations hold you back. Make your own FS, and have fun.