Emacs seems to fit what you're describing pretty closely. It can render as a GUI and TUI even though the GUI can display things the TUI can't (like fonts/images)
It's almost like parent was intentionally hinting for someone to mention Emacs. Probably not, but the degree to which they described Emacs was kinda funny. It may be old, but it's been evolving, and I absolutely love it still. Especially now with LSP. And it's not even hard to get into, when things like Doom exist.
