Hi. What Game Creation software would be the best for a beginner to start with on Linux?
There's lots of tools available, it depends on how far down the rabbit hole you want to go. I mean for instance, some people make games in Scratch and Roblox (which, whether you want to go that route, entirely up to you, but they're fairly restrictive in what they can do). Then there's the fully featured ones, such as Unreal Engine, Unity, or Godot. And everything in-between. RPGMaker is quite popular for making simple-er 2d style games in that traditional JRPG style.
It all depends on what you're looking to do.
I'll add that Godot is nice because you don't need to make an account just to use it, and "installing" it amounts to downloading its executable.
I thought of starting with 2D, either a scroller or a bullet hell, to get the basics learned.
Awesome, I'll check it out.
A lot of engines will do just that. If you're looking into going further after that point, it could be worth starting with something like Godot. It will take a bit of learning, but what you learn from there you can make pretty complex games.
I would also recommend you either find a guide / tutorial you like, or (and I know some people frown on them because, well, money) paid online courses that you could take that would give you some insight into how the engine and game creation in that works. I've done that (the class I took was cheap, but gave me a solid foundation to work off of) and I was quite happy with the decision. But to each their own in that regard.
Another option that I would highly recommend even, if you really want to force yourself to learn, is to join a GameJam (like those on itch dot io). Those can be really fun, and force you to learn some basics within generally a short period of time.