Slipways is built on top of Unity. If your main goal is to make a game (a daunting prospect on its own), having to create an engine on top of that is probably not going to help your chances.
If your main goal is to enjoy yourself, there are very few programming tasks as varied and fulfilling as writing your own game engine. Personally, I'm glad there are alternatives.
You are not! PICO-8 was where I started, and it was a great experience - both for its community at the time and due to the constraints it imposed, making me focus on finishing games and boiling them down to the essentials.
I heartily recommend PICO-8 for anybody trying to get into hobby/solo gamedev from the programming direction.
Almost all indie devs these days use Unity or Unreal. You'll get more output out of these quicker, and that will encourage you to continue developing.
Don't be put off from writing your own engine, but it is quite a daunting task, expecially for 3D.
Besides rendering, these off the shelf engines provide tooling that make game development easier on you. Map editing, animation editing, sound editing etc all built in.
I looked hard at Unity but ultimately couldn’t get myself past the learning curve and went with MonoGame instead, this allowed me to prototype my game idea in a mere 8-12 hours of coding without any clunky interface getting in the way.
I am not sure if I made the right choice or not but the engine I’m working on is indeed very satisfying to build though I am aware I could have had a playable game by now instead of still be implementing hand cranked shader animations and trying to architect a custom rendering stack… but I figure if it’s not one thing it’s another!
Plus if you do succeed don’t you end up owing Unity a bunch of money?
You made the right choice if you're still working at it. Staying on target is more important than the bad choices you might make - otherwise you'll end up like me and thousands others who are indecisive and consequently produce nothing.
If your main goal is to enjoy yourself, there are very few programming tasks as varied and fulfilling as writing your own game engine. Personally, I'm glad there are alternatives.