SyntaxBomb - Indie Coders

This is the stable version:

https://github.com/AdeptLanguage/Adept

This is the next version:

https://github.com/IsaacShelton/Adept3x

If you don't want to use heavy code editors like VSCode or Sublime, there is syntax highlighting for Geany:

https://github.com/geany/geany/issues/3917

The developer also supports Vim. But I doubt anyone here will like Vim.