Very cool - nice tutorial!
I've released a few games with my home made engine (most recently https://poki.com/en/g/blaze-drifter)
My best advice is only write enough engine to support the game you want to make. Also don't try and write an editor, but add debug/editor tools directly in the game. With each game you make, you can add one or two new features to the engine, and slowly build up the feature set to be able to make larger games.
I started with a simple on screen 'watch variable', so I can visually inspect values over time. I added simple click drag edit support so I can then edit a value too. Over time I've added a (very simple) console, a simple immediate mode debug UI, graphing for the watch variables, and a little track editor (with the debug UI). Again the key is to build only what you need and only when you need it. It sounds quite a lot when I write it down, but it's all super simple and only supports the barest features that I actually need.
