[socalgal2]

The instinct to make a game engine is it's well known how to do it and you just follow examples all over the the place and each few days you check off a box and feel like you're making progress. It's much easier than making a game itself. There is no known list of do X, do Y, do Z that leads to a game. In that sense, games are harder than game engines because a game is unknown, a game engine is well known.

IF you want to make a game engine, building one is progress

If you want to make a game, building a game engine is the illusion of progress. When you're done making the engine you'll be no further along on your game than if you'd used an existing engine. Usually you'll be behind because those other engines have so many features and tools that you have yet to implement. Sure, you don't need every feature, but you may be surprised at all of the little things you end up having to write.