After check 0xchat source code (nostr:npub10td4yrp6cl9kmjp9x5yd7r8pm96a5j07lk5mtj2kw39qf8frpt8qm9x2wl). I will give Flutter a try 😅. Other than that, Flutter have plenty of library for building nice UI on Linux, and I can use Rust for backend as well, seems decent choice.