Fine, I do this since several decades.
I use an editor-construction kit named "Emacs" to build my own Editor, and IDE, and git porcelain, and organizer, and wiki. And many things more.
IDE with e.g. LSP integration, rustix and many other programmer-related modes and enhancements like tree-sitter. Git porcelain with magit. Organizer with Org-Mode. Wiki with denote.