Let's see, of the games I still have on Itch, one is made with Ren'Py, another with Twine, a couple with ZXBasic, and two more with sdlBasic and FreeBasic, respectively. But most are just coded from scratch in HTML5.
Viewing post in what software are people using
unity has problems, the biggest is random lag or crashes. Unity is more forces on high-end PC and console which leads to many lower end PC users complaining about your game optimization. Not only you need to optimize your game in Unity but you cant fix certain bugs even well known bugs are never fix. So i really dont recommend unity for first timers, it has problems that leads to other problems.
Godot is a good alternative but there is no document and it reportedly has lots of bugs, way more than unity. It also has a bad UI even when i try it, i did not know how to add a simple model or visit the game view screen. No real time editor so you cant test some things and go back on the code.
The best one I recommend is Xenko Engine, its open source and written for C#. It can even be exported for the Xbox which Godot cant do. The down side of this engine is it only runs on Microsoft Windows machines.