My recommendation is Fedora Silverblue, or to be specific, uBlue. SB is already great, but uBlue ships with some better QOL-defaults. It's not a fork of SB tho, it's just a project for custom images.
You can rebase anytime you want to a SteamOS-clone, KDE spin, and so on, with one command and without any traces.

Why? Here are my reasons for you:

stay out of my way (just work), ex: i dont get any notifications i dont want from the system itself and all i need to do is type 3 letters to initiate an update

uBlue is even less.
It updates automatically in the background and creates the new (updated) image for you.
BUT, not similar to Windows, where the OS just decides to shut off your PC randomly.

You can still keep using your PC and don't notice the staged updates at all.
And when you switch on your device the next time, like once a week or so, you automatically use the new image.

requires little ram to actually use (not really needed due to hardware but simply to reduce the pcs noise as much as possible, bonus points if programs generally do the same thing on it)

That's the same on every distro, doesn't matter. SB is very lean though imo, though not as much as Debian or Arch of course, but therefore very comfortable.
Also:

1. Unused RAM is wasted RAM. As long as it doesn't bottleneck you, why care?
2. This is why
3. If you want to keep your PC silent, change the energy profile or install some fan control software/ more silent fans (Noctua f.e.)

Doesnt require too much fiddling (endevouros never needs this generally, when installing something it usually installs everything you need for things to work, i prefer GUIs usually but if its deadsimple commands like yay its fine as well)

Silverblue "just works" OOTB. It is very user friendly imo and I basically never open the terminal, only, when I have to install something through Distrobox, which isn't often. But 99% is available as Flatpak in the Software Center.

I game and stream so both would need to be doable as easy as possible (i use obs, when it comes to games i usually do emulation and try to avoid proton)

Again, doesn't matter which distro. Almost everything is available as Flatpak.

Why Silverblue?

• As streamer, you want something to always work reliably. An immutable distro ensures that by atomic updates and perfect reproducibility (less bugs and more secure)
• Easy to use (if you forget how traditional distros work)
• Huge software access: you work with containers all the time, and with Distrobox (pre-installed) you can access the AUR, Debian, and much much morenon the same distro! ^(works on other distros aswell...)
• Almost impossible to break
• Flexible: you can always rebase to another spin or variant with one command and without any trace
• And much more.

I would advice against Arch based distros like Garuda, Endeavor, and so on.

I don't see much reasons to use them and due to their nature, they might be not as reliable. It would suck if your install breaks before or while streaming... With SB, you can roll back to your old image in just seconds and everything works again, even if you fucked up.

Most stuff you mentioned works on every distro, you don't need Arch for that. If you like it's UI, then go for Kinoite (the SB KDE spin), or, better, uBlue KDE.