for UE4, it's C++, but you can start using the (kind of) successor of kismet: "blueprints".

I am well aware of the licensing for all of those engines.

You can use Unity for free as long as you don't make a gross revenue of 100,000$+ per fiscal year. Then again if you make so much money buying license for 1,500$ (3,000 if you also want to export to android/iOS) wouldn't be a problem.

Unreal Engine 4's 5% of gross revenue royalties can end up being a lot more money then Unity's 1500$ license. But you don't have to pay them anything while you're working on your game, and you don't have to pay them if you're not making above certain amount of money. It's a bit annoying you have to keep sending them detailed reports of how much money you make along with royalty payments all the time. I think Unity's licensing is much better. But I'd probably still rather use UE4 over Esenthel Engine.

Esenthel Engine is 11.40 USD / month or 114 USD / year regardless if you're making money on your games or not. And considering the developer says: "The engine is free to try in demo mode, however using it requires purchasing a license" I'd assume that means you have to get subscription and pay money during the whole development process (correct me if I am wrong).