Game Development

Godot uses a language which is similar to Python, GDScript. I avoided Godot for a long time because I thought it was some sort of kiddy language meant for children to make games. I was wrong

GDScript is actually very robust. It uses a familiar syntax to python, and it is built using C++

You can also use C# and C++ if you don't want to use GDScript. I use C# for most of my actual game logic, and then use GDScript for stuff where performance isn't an issue or for something that only takes a couple minutes to write.

Godot also has a shader language similar to HLSL, and it's a robust option, too. It has built in networking, exports to Android very easily.

You can use libraries really easily, so if you have a C# or C++library you want to use, it's super simple.

I recommend you at least try it, the whole engine is really small in comparison to Unity or Unreal and there is no installation. You just download it and run the exe

Godot also runs on Linux, since that's important to you.

It doesn't matter too much which engine you pick up.

If you feel like writing in c++ and can deal with unreals longer compile times go for it.

If you want to write in c# go with unity if you want lots of documentation and tutorials. Go with godot if you want something open source.

The skills you'll pick up with any choice transfer very easily to another choice. Don't stress too much. There are no wrong choices.

Edit. On whether picking up c# is easy if you know c++. That's where I came from too and there was like. No learning curve at all. It will feel very easy and natural.

Edit2. On which one scales better for large worlds. None and all of them. It's entirely up to you to make your code efficient for large scale projects. No engine will help you there. They all have the basic tools for you to optimize your code though.

Tldr: literally doesn't matter which one you pick. If you want a stranger to pick for you. Go with godot. Can't go wrong with open source and quick iteration times.