Hey! Textmode is kind of niche but when done "properly" can both look very nice and be rather easy to work with. The way I see it, as I'm not aware of an actual textmode-compatible game engine editor existing, there's two options to implement textmode assets in a game:
-Either create a custom system or editor to interpret and manipulate textmode assets, create levels and objects and export the necessary data (which would allow for more creative freedom and ease of use, at the cost of having to make the editor "engine" yourself), or
-Improvise! I used LDtk with custom, pre-made tilesets (basically, copies of the "main" textmode tileset with several different color combinations) to make some nice looking results! It's more limited in the sense of available colors and creative freedom, and the duplicated tilesets can be a bit cumbersome to navigate, but allows the use of a really good, easy to use game-focused tile-based editor :)
Also, I'd definitely research the game-making aspect of Playscii, as it's intended to be a python-based game development tool. I'm certain it can export useful game data in at least *some* way, but it's always been outside of my scope of expertise so I can't provide much useful info on that.