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.