As Megalomaniak said, the sky is the limit as to what is 'impossible'. Godot is open source, meaning that you can add anything to the engine with enough time and effort. It might take a lot of learning, and you might find adding some feature isn't worth the effort, but it is all achivable.
If you don't have any specific idea, as you said above, then it doesn't really matter what features are included or not, since there isn't a clear goal/project/idea/game in mind to reach.
I would recommend taking tutorials and writing a design document for the game you want to create. Then you can narrow down the design document into small tasks, each small and hopefully easily done on their own. Tackling something small is way easier than tackling something giant. Making games are a giant process, and it should to be taken one step at a time to avoid burnout.
If you're trying to keep your options open, making sure you won't have to change engines halfway through development, I wouldn't worry about it. Most game engines follow the same underlying structure and programming is universal on the basic level. Any advance features of one engine can be reproduced in another, it might take some work to do it, but it can be done.
I've moved from Pygame to ImpactJS, then Unity, then Godot, then Unreal engine, then back Godot, then back to Unity, and now back once again to Godot. The transition wasn't terribly difficult and I found that each engine has their own strengths and weaknesses. It really depends on what feels right at the time and what you think will best support your project.
All of that is to say, I would recommend taking tutorials and then thinking about what game you want to make. The games presented in tutorials might not be the most interesting games you can create, but they teach you the fundamentals of game programming and game design. Then after you've taken a few tutorials, you will be better equiped to decide what you need in your game and which features are required to make your game.
No one knows everything. Big features like you see in big games (like Call of duty, Destiny, World of Warcraft, Final fantasy, ect) are done with large/huge teams that have specialized knowledge in their field of game development. Most indie games don't have a huge team behind them, and so they generally are smaller in scope. Undertale doesn't have any flashy features, Minecraft doesn't either. Neither of them are bad in terms of game design, and both of them are well liked in the gaming world.
Game development will require learning, practice, and patience. I'm sure you can be a great game developer! Take some tutorials and start making games! Your first games might not be what you expected, but they are the first steps on the path that is game development!
