Download Nim language here: https://nim-lang.org/install_windows.html
Clone it to your local folder:
https://github.com/KMiNT21/minimal-caps-lock-lang-switcher.git
Then build it to exe by command:
nim c --app:gui caps_lock_lang_switcher.nim
Now you can add caps_lock_lang_switcher.exe to your Startup