Hi,
I’m going to say that at a high level it doesn’t make much of a difference. Some distros will make claims they have tweaks for gaming but for most players I doubt you’ll notice the difference. Almost all distributions make it easy to get Nvidia drivers working these days so I wouldn’t worry about that.
I’d say to pick the distribution based on other factors, such as update policy (rolling vs stable) or desktop environment you prefer.
I wanted to wait to the end to mention Manjaro has some controversial aspects to it. In terms of how the project handles money and leadership. I’d personally not recommend it but that has nothing to do with gaming.
I don’t think you really do anymore. I’d consider myself an experienced Linux user. I’ve been using it as a my desktop OS for over 20 years. I’ve also used Linux heavily through my career and am completely comfortable with the command line.
With recent installs of Fedora the only thing I use the command line for is the initial setup of the multimedia codecs. After that I haven’t been required to touch it.
I used to consider a terminal required to keep your desktop Linux system running. Now I look at is as an optional install for programmers.