Help needed: State of graphics stack on linux for Gaming (OPTIMUS laptop)

This probably was asked countless times already, but given the amount of possible combinations of all the hardware and software, this is probably not surprising.

So, I do have some experience with linux. I ssh into my ubuntu server a lot, I do many bash/terminal tricks, so can't really call myself a newbie in Linux. However, for gaming I would use Windows for as long as I remember myself. With the release of KDE Plasma 6 and Vulkan support getting better, I was thinking about giving it a go, but I'm stuck.

When launching a game that natively supports linux (Dota 2) from Steam, pretty much nothing happens. I see in terminal that there are some errors, but archwiki states that this is normal:

Wrong ELF class

If you see this message in Steam's console output

ERROR: ld.so: object '~/.local/share/Steam/ubuntu12_32/gameoverlayrenderer.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS32): ignored.

you can safely ignore it. It is not really any error: Steam includes both 64- and 32-bit versions of some libraries and only one version will load successfully. This "error" is displayed even when Steam (and the in-game overlay) is working perfectly.

Other than that I see no errors or anything.

I'm running Arch linux with KDE Plasma 6.0.1, with default Wayland session. My laptop is an Acer Nitro 5 with NVIDIA GPU and I guess also Intel integrated video card. Here are the details:

I have no idea honestly about which driver I have installed, but I did install nvidia package. I'm not sure if it's being used. I also don't know anything about Mesa. Also, this is from my Info Center:

I don't even know what is Xwayland and why I have it installed, probably some dependency of KDE.

At this point I'm not even sure what I'm using (is it pure wayland, or x11, or some hybrid of using both), if I have correct GPU drivers (do I have correct drivers for just one of the two video cards, for both, or none at all), if my NVIDIA GPU is even working, if it's being used to run a game or not, and if I have all necessary packages to run Vulkan.

At this point, how do I troubleshoot all of this mess?